2-pyrazine carboxamides as spleen tyrosine kinase inhibitors

ABSTRACT

The invention provides certain pyrazine-2-carboxamide compounds of the Formula (I) or pharmaceutically acceptable salts thereof, wherein A, B, and X are as defined herein. The invention also provides pharmaceutical compositions comprising such compounds, and methods of using the compounds for treating diseases or conditions mediated by Spleen Tyrosine Kinase (Syk).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Phase application under 35 U.S.C. §371 of PCT/US15/19349, filed, Mar. 9, 2015, which claims priority from U.S. provisional application No. 61/952,474 filed Mar. 13, 2014.

FIELD OF THE INVENTION

The present invention relates to certain 2-pyrazine carboxamide compounds of the Formula (I) (also referred to herein as the “compounds of the Formula (I)” or “compounds of Formula (I)”) which are inhibitors of Spleen Tyrosine Kinase (Syk) kinase activity, or are prodrugs thereof. The present invention also provides compositions comprising such compounds, and methods of using such compounds for treating conditions or disorders associated with inappropriate Syk activity, in particular in the treatment and prevention of disease states mediated by Syk. Such disease states may include inflammatory, allergic and autoimmune diseases, for example, asthma, chronic obstructive pulmonary disease (COPD), adult respiratory distress syndrome (ARDS), ulcerative colitis, Crohn's disease, bronchitis, dermatitis, allergic rhinitis, psoriasis, scleroderma, urticaria, rheumatoid arthritis, idiopathic thrombocytopenic purpura (ITP), multiple sclerosis, cancer, HIV and lupus.

BACKGROUND OF THE INVENTION

Spleen Tyrosine Kinase (Syk) is a protein tyrosine kinase which has been described as a key mediator of immunoreceptor signalling in a host of inflammatory cells including mast cells, B-cells, macrophages and neutrophils. These immunoreceptors, including Fc receptors and the B-cell receptor, are important for both allergic diseases and antibody-mediated autoimmune diseases and thus pharmacologically interfering with Syk could conceivably treat these disorders.

Allergic rhinitis and asthma are diseases associated with hypersensitivity reactions and inflammatory events involving a multitude of cell types including mast cells, eosinophils, T cells and dendritic cells. Following exposure to allergen, high affinity immunoglobulin receptors for IgE and IgG become cross-linked and activate downstream processes in mast cells and other cell types leading to the release of pro-inflammatory mediators and airway spasmogens. In the mast cell, for example, IgE receptor cross-linking by allergen leads to release of mediators including histamine from pre-formed granules, as well as the synthesis and release of newly synthesized lipid mediators including prostaglandins and leukotrienes.

Syk kinase is a non-receptor linked tyrosine kinase which is important in transducing the downstream cellular signals associated with cross-linking Fc_(epsilon)RI and or Fc_(epsilon)RI receptors, and is positioned early in the signalling cascade. In mast cells, for example, the early sequence of Fc_(epsilon)RI signalling following allergen cross-linking of receptor-IgE complexes involves first Lyn (a Src family tyrosine kinase) and then Syk. Inhibitors of Syk activity would therefore be expected to inhibit all downstream signalling cascades thereby alleviating the immediate allergic response and adverse events initiated by the release of pro-inflammatory mediators and spasmogens (Wong et al. 2004, Expert Opin. Investig. Drugs (2004) 13 (7) 743-762).

Recently, it has been shown that the Syk kinase inhibitor R112 (Rigel), dosed intranasally in a phase I/II study for the treatment of allergic rhinitis, gave a statistically significant decrease in PGD₂, a key immune mediator that is highly correlated with improvements in allergic rhinorrhea, as well as being safe across a range of indicators, thus providing the first evidence for the clinical safety and efficacy of a topical Syk kinase inhibitor. (Meltzer, Eli O.; Berkowitz, Robert B.; Grossbard, Elliott B, Journal of Allergy and Clinical Immunology (2005), 115(4), 791-796). In a more recent phase II clinical trial for allergic rhinitis (Clinical Trials.gov Identifier NCT0015089), R112 was shown as having a lack of efficacy versus placebo.

Rheumatoid Arthritis (RA) is an auto-immune disease affecting approximately 1% of the population. It is characterised by inflammation of articular joints leading to debilitating destruction of bone and cartilage. Recent clinical studies with Rituximab, which causes a reversible B cell depletion, (J. C. W. Edwards et al. 2004, New Eng. J. Med. 350: 2572-2581) have shown that targeting B cell function is an appropriate therapeutic strategy in auto-immune diseases such as RA. Clinical benefit correlates with a reduction in auto-reactive antibodies (or Rheumatoid Factor) and these studies suggest that B cell function and indeed auto-antibody production are central to the ongoing pathology in the disease.

Studies using cells from mice deficient in the Spleen Tyrosine Kinase (Syk) have demonstrated a non-redundant role of this kinase in B cell function. The deficiency in Syk is characterised by a block in B cell development (M. Turner et al. 1995 Nature 379: 298-302 and Cheng et al. 1995, Nature 378: 303-306). These studies, along with studies on mature B cells deficient in Syk (Kurasaki et al. 2000, Immunol. Rev. 176:19-29), demonstrate that Syk is required for the differentiation and activation of B cells. Hence, inhibition of Syk in RA patients is likely to block B cell function, and thereby reduce Rheumatoid Factor production. In addition to the role of Syk in B cell function, and of further relevance to the treatment of RA, is the requirement for Syk activity in Fc receptor (FcR) signalling. FcR activation by immune complexes in RA has been suggested to contribute to the release of multiple pro-inflammatory mediators.

SUMMARY OF THE INVENTION

The present invention provides novel compounds that are potent inhibitors of Syk, or are prodrugs thereof, as well as pharmaceutical compositions containing them. As Syk inhibitors compounds of Formula (I) are useful in the treatment and prevention of diseases and disorders mediated by the Syk protein; such diseases and disorders include, but are not limited to, asthma, COPD, rheumatoid arthritis, cancer and idiopathic thrombocytopenic purpura.

DETAILED DESCRIPTION OF THE INVENTION Definitions

The terms used herein have their ordinary meaning and the meaning of such terms is independent at each occurrence thereof. That notwithstanding and except where stated otherwise, the following definitions apply throughout the specification and claims. Chemical names, common names, and chemical structures may be used interchangeably to describe the same structure. If a chemical compound is referred to using both a chemical structure and a chemical name, and an ambiguity exists between the structure and the name, the structure predominates. These definitions apply regardless of whether a term is used by itself or in combination with other terms, unless otherwise indicated. Hence, the definition of “alkyl” applies to “alkyl” as well as the “alkyl” portions of “hydroxyalkyl,” “fluoroalkyl,” “—O-alkyl,” etc.

As used herein, and throughout this disclosure, the following terms, unless otherwise indicated, shall be understood to have the following meanings:

A “patient” is a human or non-human mammal. In one embodiment, a patient is a human. In another embodiment, a patient is a chimpanzee.

The term “therapeutically effective amount” as used herein, refers to an amount of the compound of Formula (I) and/or an additional therapeutic agent, or a composition thereof that is effective in producing the desired therapeutic, ameliorative, inhibitory or preventative effect when administered to a patient suffering from a disease or condition mediated by Syk. In the combination therapies of the present invention, a therapeutically effective amount can refer to each individual agent or to the combination as a whole, wherein the amounts of all agents administered are together effective, but wherein the component agent of the combination may not be present individually in an effective amount.

The term “preventing,” as used herein with respect to cancer or an inflammatory disease or disorder, refers to reducing the likelihood of cancer pain or an inflammatory disease or disorder.

The term “alkyl,” as used herein, refers to an aliphatic hydrocarbon group having one of its hydrogen atoms replaced with a bond having the specified number of carbon atoms. In different embodiments, an alkyl group contains from 1 to 6 carbon atoms (C₁-C₆ alkyl) or from 1 to 3 carbon atoms (C₁-C₃ alkyl). Non-limiting examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, isopentyl, n-hexyl, isohexyl and neohexyl. In one embodiment, an alkyl group is linear. In another embodiment, an alkyl group is branched.

The term “alkenyl,” as used herein, refers to an aliphatic hydrocarbon group containing at least one carbon-carbon double bond and having one of its hydrogen atoms replaced with a bond. An alkenyl group may be straight or branched and contain from about 2 to about 15 carbon atoms. In one embodiment, an alkenyl group contains from about 3 to 6 carbon atoms. Non-limiting examples of alkenyl groups include ethenyl, propenyl, n-butenyl, 3-methylbut-2-enyl, n-pentenyl, octenyl and decenyl. The term “C₂-C₆ alkenyl” refers to an alkenyl group having from 2 to 6 carbon atoms. Unless otherwise indicated, an alkenyl group is unsubstituted.

The term “fluoroalkyl,” as used herein, refers to an alkyl group as defined above, wherein one or more of the alkyl group's hydrogen atoms has been replaced with a fluorine. In one embodiment, a fluoroalkyl group has from 1 to 6 carbon atoms. In another embodiment, a fluoroalkyl group has from 1 to 3 carbon atoms. In another embodiment, a fluoroalkyl group is substituted with from 1 to 3 F atoms. Non-limiting examples of fluoroalkyl groups include —CHF, —CHF₂, and —CF₃. The term “C₁-C₃ fluoroalkyl” refers to a fluoroalkyl group having from 1 to 3 carbon atoms.

The term “alkoxy” as used herein, refers to an —O-alkyl group, wherein an alkyl group is as defined above. Non-limiting examples of alkoxy groups include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy and t-butoxy. An alkoxy group is bonded via its oxygen atom to the rest of the molecule.

The term “aryl,” as used herein, refers to an aromatic monocyclic or multicyclic ring system comprising from about 6 to about 14 carbon atoms. In one embodiment, an aryl group contains from about 6 to 10 carbon atoms (C₆-C₁₀ aryl). In another embodiment an aryl group is phenyl. Non-limiting examples of aryl groups include phenyl and naphthyl.

The term “cycloalkyl,” as used herein, refers to a saturated ring containing the specified number of ring carbon atoms, and no heteroatom. In a like manner the term “C₃-C₆ cycloalkyl” refers to a saturated ring having from 3 to 6 ring carbon atoms. Non-limiting examples of monocyclic cycloalkyls include cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl.

The term “halo,” as used herein, means —F, —Cl, —Br or —I. In one embodiment, a halo group is —F or —Cl. In another embodiment, a halo group is —F.

The term “heteroaryl,” as used herein, refers to an aromatic monocyclic or multicyclic ring system comprising about 5 to about 14 ring atoms, wherein from 1 to 3 of the ring atoms is independently N, O, or S and the remaining ring atoms are carbon atoms. In one embodiment, a heteroaryl group has 5 to 10 ring atoms. In another embodiment, a heteroaryl group is monocyclic ring system and has 5 or 6 ring atoms. In another embodiment, a heteroaryl group is a bicyclic ring system. A heteroaryl group is joined via a ring carbon atom. The term “heteroaryl” also includes a heteroaryl as defined above fused to a heterocycle as defined below. The term “heteroaryl” also encompasses a heteroaryl group, as defined above, which is fused to a benzene, a cyclohexadiene or a cyclohexene ring. Non-limiting examples of heteroaryls include pyridyl, pyrazinyl, furanyl, thienyl, pyrimidinyl, pyridone (including N-substituted pyridones), isoxazolyl, isothiazolyl, oxazolyl, oxadiazolyl, thiazolyl, pyrazolyl, furyl, pyrrolyl, triazolyl, 1,2,4-thiadiazolyl, pyrazinyl, pyridazinyl, indolyl, quinoxalinyl, phthalazinyl, oxindolyl, imidazo[1,2-a]pyridinyl, imidazo[2,1-b]thiazolyl, and the like. In one embodiment, a heteroaryl group is a 5-membered heteroaryl. In another embodiment, a heteroaryl group is a 6-membered heteroaryl.

The term “heterocyclyl” or “heterocycle”, “as used herein, refers to a non-aromatic saturated or partially saturated monocyclic or multicyclic ring system containing 3 to 11 ring atoms, wherein from 1 to 4 of the ring atoms are independently O, S, or N, and the remainder of the ring atoms are carbon atoms. In one embodiment, a heterocyclyl group is monocyclic and has from 3 to 7 ring atoms. In another embodiment, a heterocyclyl group is monocyclic and has from about 4 to 7 ring atoms. In another embodiment, a heterocyclyl group is bicyclic and has from 7 to 11 ring atoms. In still another embodiment, a heterocyclyl group is monocyclic and has 5 or 6 ring atoms. In one embodiment, a heterocyclyl group is monocyclic. In another embodiment, a heterocyclyl group is bicyclic. A heterocyclyl group can be joined to the rest of the molecule via a ring carbon or ring nitrogen atom. The nitrogen or sulfur atom of the heterocyclyl can be optionally oxidized to the corresponding N-oxide, S-oxide or S,S-dioxide. Non-limiting examples of monocyclic heterocyclyl rings include oxetanyl, piperidyl, pyrrolidinyl, piperazinyl, morpholinyl, thiomorpholinyl, thiazolidinyl, dihydropyranyl, pyran, 1,4-dioxanyl, tetrahydrofuranyl, tetrahydrothiophenyl, delta-lactam, delta-lactone, and the like.

The term “substituted” means that one or more hydrogens on the atoms of the designated are replaced with a selection from the indicated group, provided that the atoms' normal valencies under the existing circumstances are not exceeded, and that the substitution results in a stable compound. Combinations of substituents and/or variables are permissible only if such combinations result in stable compounds. By “stable compound’ or “stable structure” is meant a compound that is sufficiently robust to survive isolation to a useful degree of purity from a reaction mixture, and formulation into an efficacious therapeutic agent.

When any substituent or variable occurs more than one time in any constituent or the compound of Formula (I), its definition on each occurrence is independent of its definition at every other occurrence, unless otherwise indicated. For example, description of radicals which include the expression “—N(C₁-C₃ alkyl)₂” means —N(CH₃)(CH₂CH₃), —N(CH₃)(CH₂CH₂CH₃), and —N(CH₂CH₃)(CH₂CH₂CH₃), as well as —N(CH₃)₂, —N(CH₂CH₃)₂, and —N(CH₂CH₂CH₃)₂.

The term “in purified form,” as used herein, refers to the physical state of a compound after the compound is isolated from a synthetic process (e.g., from a reaction mixture), a natural source, or a combination thereof. The term “in purified form,” also refers to the physical state of a compound after the compound is obtained from a purification process or processes described herein or well-known to the skilled artisan (e.g., chromatography, recrystallization and the like), in sufficient purity to be characterizable by standard analytical techniques described herein or well-known to the skilled artisan.

It should also be noted that any carbon as well as heteroatom with unsatisfied valences in the text, schemes, examples and tables herein is assumed to have the sufficient number of hydrogen atom(s) to satisfy the valences.

One or more compounds of the invention may exist in unsolvated as well as solvated forms with pharmaceutically acceptable solvents such as water, ethanol, and the like, and it is intended that the invention embrace both solvated and unsolvated forms. “Solvate” means a physical association of a compound of this invention with one or more solvent molecules. This physical association involves varying degrees of ionic and covalent bonding, including hydrogen bonding. In certain instances the solvate will be capable of isolation, for example when one or more solvent molecules are incorporated in the crystal lattice of the crystalline solid. “Solvate” encompasses both solution-phase and isolatable solvates. Non-limiting examples of suitable solvates include ethanolates, methanolates, and the like. “Hydrate” is a solvate wherein the solvent molecule is H₂O.

The compounds of Formula (I) may contain one or more stereogenic centers and can thus occur as racemates, racemic mixtures, single enantiomers, diastereomeric mixtures and individual diastereomers. Additional asymmetric centers may be present depending upon the nature of the various substituents on the molecule. Each such asymmetric center will independently produce two optical isomers and it is intended that all of the possible optical isomers and diastereomers in mixtures and as pure or partially purified compounds are included within the ambit of this invention. Any formulas, structures or names of compounds described in this specification that do not specify a particular stereochemistry are meant to encompass any and all existing isomers as described above and mixtures thereof in any proportion. When stereochemistry is specified, the invention is meant to encompass that particular isomer in pure form or as part of a mixture with other isomers in any proportion.

Diastereomeric mixtures can be separated into their individual diastereomers on the basis of their physical chemical differences by methods well known to those skilled in the art, such as, for example, by chromatography and/or fractional crystallization. Enantiomers can be separated by converting the enantiomeric mixture into a diastereomeric mixture by reaction with an appropriate optically active compound (e.g., chiral auxiliary such as a chiral alcohol or Mosher's acid chloride), separating the diastereomers and converting (e.g., hydrolyzing) the individual diastereomers to the corresponding pure enantiomers. Also, some of the compounds of Formula (I) may be atropisomers (e.g., substituted biaryls) and are considered as part of this invention. Enantiomers can also be separated by use of chiral HPLC column.

It is also possible that the compounds of Formula (I) may exist in different tautomeric forms, and all such forms are embraced within the scope of the invention.

All stereoisomers (for example, geometric isomers, optical isomers and the like) of the present compounds (including those of the salts and solvates of the compounds as well as the salts, solvates and esters of the prodrugs), such as those which may exist due to asymmetric carbons on various substituents, including enantiomeric forms (which may exist even in the absence of asymmetric carbons), rotameric forms, atropisomers, and diastereomeric forms, are contemplated within the scope of this invention. Individual stereoisomers of the compounds of the invention may, for example, be substantially free of other isomers, or may be admixed, for example, as racemates or with all other, or other selected, stereoisomers. The chiral centers of the present invention can have the S or R configuration as defined by the IUPAC 1974 Recommendations.

The compounds of Formula (I) can form salts which are also within the scope of this invention. Reference to a compound of Formula (I) herein is understood to include reference to salts thereof, unless otherwise indicated. The term “salt(s)”, as employed herein, denotes acidic salts formed with inorganic and/or organic acids, as well as basic salts formed with inorganic and/or organic bases. In addition, when a compound of Formula (I) contains both a basic moiety, such as, but not limited to a pyridine or imidazole, and an acidic moiety, such as, but not limited to a carboxylic acid, zwitterions (“inner salts”) may be formed and are included within the term “salt(s)” as used herein. Such acidic and basic salts used within the scope of the invention are pharmaceutically acceptable (i.e., non-toxic, physiologically acceptable) salts. Salts of the compounds of Formula (I) may be formed, for example, by reacting a compound of Formula (I) with an amount of acid or base, such as an equivalent amount, in a medium such as one in which the salt precipitates or in an aqueous medium followed by lyophilization.

Exemplary acid addition salts include acetates, ascorbates, benzoates, benzenesulfonates, bisulfates, borates, butyrates, citrates, camphorates, camphorsulfonates, fumarates, hydrochlorides, hydrobromides, hydroiodides, lactates, maleates, methanesulfonates, naphthalenesulfonates, nitrates, oxalates, phosphates, propionates, salicylates, succinates, sulfates, tartarates, thiocyanates, toluenesulfonates (also known as tosylates), 1-hydroxy-2-naphthoates (also known as xinafoates) and the like. Additionally, acids which are generally considered suitable for the formation of pharmaceutically useful salts from basic pharmaceutical compounds are discussed, for example, by P. Stahl et al, Camille G. (eds.) Handbook of Pharmaceutical Salts. Properties, Selection and Use. (2002) Zurich: Wiley-VCH; S. Berge et al, Journal of Pharmaceutical Sciences (1977) 66(1) 1-19; P. Gould, International J. of Pharmaceutics (1986) 33 201-217; Anderson et al, The Practice of Medicinal Chemistry (1996), Academic Press, New York; and in The Orange Book (Food & Drug Administration, Washington, D.C. on their website). These disclosures are incorporated herein by reference.

Exemplary basic salts include ammonium salts, alkali metal salts such as sodium, lithium, and potassium salts, alkaline earth metal salts such as calcium and magnesium salts, salts with organic bases (for example, organic amines) such as dicyclohexylamines, t-butyl amines, and salts with amino acids such as arginine, lysine and the like. Basic nitrogen-containing groups may be quarternized with agents such as lower alkyl halides (e.g., methyl, ethyl, and butyl chlorides, bromides and iodides), dialkyl sulfates (e.g., dimethyl, diethyl, and dibutyl sulfates), long chain halides (e.g., decyl, lauryl, and stearyl chlorides, bromides and iodides), aralkyl halides (e.g., benzyl and phenethyl bromides), and others.

The present invention further includes the compounds of Formula (I) in all their isolated forms. For example, the above-identified compounds are intended to encompass all forms of the compounds such as, any solvates, hydrates, stereoisomers, and tautomers thereof.

As used herein, the term “composition” is intended to encompass a product comprising the specified ingredients in the specified amounts, as well as any product which results, directly or indirectly, from combination of the specified ingredients in the specified amounts.

In the compounds of generic Formula (I), the atoms may exhibit their natural isotopic abundances, or one or more of the atoms may be artificially enriched in a particular isotope having the same atomic number, but an atomic mass or mass number different from the atomic mass or mass number predominantly found in nature. The present invention is meant to include all suitable isotopic variations of the compounds of generic Formula (I). For example, different isotopic forms of hydrogen (H) include protium (¹H) and deuterium (²H). Protium is the predominant hydrogen isotope found in nature. Enriching for deuterium may afford certain therapeutic advantages, such as increasing in vivo half-life or reducing dosage requirements, or may provide a compound useful as a standard for characterization of biological samples. Isotopically-enriched compounds within generic Formula (I) can be prepared without undue experimentation by conventional techniques well known to those skilled in the art or by processes analogous to those described in the examples herein using appropriate isotopically-enriched reagents and/or intermediates.

Compounds of the Invention

The present invention provides a compound of Formula (I) or a pharmaceutically acceptable salt thereof, wherein A, B, and X are as set forth below. Described below are embodiments of the compound of Formula (I).

In embodiment no. 1, the invention provides a compound of the Formula (I),

or a pharmaceutically acceptable salt thereof, wherein

-   X is N(H) or O; -   B is a 5- to 10-membered mono- or bicyclic heteroaryl optionally     containing 1 heteroatom in addition to the illustrated X atom,     selected from the group consisting of N, O, and S;     -   wherein B is unsubstituted or substituted by one to three R³         moieties, wherein each R³ moiety is independently selected from         the group consisting of C₁-C₃ alkyl, C₁-C₃ alkoxy, C₁-C₃         fluoroalkyl, C₁-C₃ hydroxyalkyl, di(C₁-C₃ alkyl)sulfonium, halo,         hydroxy, amino, (C₁-C₃ alkyl)amino, di(C₁-C₃ alkyl)amino,         —N(H)SO₂—(C₁-C₃ alkyl), —CO₂H, —C(O)NH₂, —C(O)N(H)(C₁-C₃ alkyl),         —C(O)N(H)(C₁-C₃ alkyl)₂, —CH₂O—(C₁-C₄ alkylene)-OH, phenyl,         methyl pyrazolyl, pyridyl, and —CH₂CH₂-pyrrolidon-2-yl;     -   or two R³ moieties when substituted on adjacent carbon atoms of         B, together with their attached carbon atoms, form a dioxanyl or         dioxolanyl ring; -   A is selected from the group consisting of:     -   (a)

-   -    wherein         -   Y is —CH₂—, —S(O)₂—, or —O—;         -   R¹¹ and R¹² are independently H or F; and         -   the subscript n is 1 or 2;         -   the subscript n′ is 0 or 1; or     -   (b)

-   -    wherein         -   R^(a) and R^(b) are independently H, C₁-C₃ alkyl, or (C₁-C₃             alkoxy)methyl;         -   R^(c) is H, C₁-C₆ alkyl, C₁-C₃ fluoroalkyl, C₃-C₆             cycloalkyl, —(CH₂)_(r)OR¹³, —C(O)NH₂, —C(O)N(H)(C₁-C₃             alkyl), —C(O)N(C₁-C₃ alkyl)₂, —(CH₂)_(r)S(O)_(t)R¹⁴,             —(CH₂)_(r)-phenyl, or —(CH₂)_(r)N(H)C(O)—(C₁-C₃ alkyl);             -   R¹³ is H or C₁-C₃ alkyl; and             -   R¹⁴ is C₁-C₃ alkyl;             -   the subscript r is 1 or 2;             -   the subscript t is 0, 1, or 2;         -   R^(d) is H or C₁-C₃ alkyl.

In embodiment no. 2, the invention provides a compound of the Formula (I), wherein B is selected from the group consisting of:

wherein B is unsubstituted or substituted by one to two R³ moieties, and A is as set forth in embodiment no. 1.

In embodiment no. 3, the invention provides a compound of the Formula (I), wherein B is as set forth in embodiment no. 2, and is unsubstituted or substituted by one to two R³ moieties selected from the group consisting of chloro, fluoro, bromo, methyl, ethyl, trifluoromethyl, methoxy, phenyl, dimethylsulfonium, pyridyl, and —CH₂CH₂-pyrrolidon-2-yl; and A is as set forth in embodiment no. 1.

In embodiment no. 4, the invention provides a compound of the Formula (I), wherein

-   A is

-   -   Y is —CH₂—, —S(O)₂—, or —O—;     -   R¹¹ and R¹² are independently H or F; and     -   the subscript n is 1 or 2;     -   the subscript n′ is 0 or 1; and

-   B is as set forth in any one of embodiment nos. 1-3.

In embodiment no. 5, the invention provides a compound of the Formula (I), wherein A is selected from the group consisting of:

and B is as set forth in any one of embodiment nos. 1-3.

In embodiment no. 6, the invention provides a compound of the Formula (I), wherein A is selected from the group consisting of:

and B is as set forth in any one of embodiment nos. 1-3.

In embodiment no. 7, the invention provides a compound of the Formula (I), wherein A is as set forth in embodiment no. 6, and B is as set forth in embodiment no. 3.

In embodiment no. 8, the invention provides a compound of the Formula (I), wherein

-   -   A is

-   -    wherein         -   R^(a) and R^(b) are independently H, C₁-C₃ alkyl, or (C₁-C₃             alkoxy)methyl;         -   R^(c) is H, C₁-C₆ alkyl, C₁-C₃ fluoroalkyl, C₃-C₆             cycloalkyl, —(CH₂)_(r)OR¹³, —C(O)NH₂, —C(O)N(H)(C₁-C₃             alkyl), —C(O)N(C₁-C₃ alkyl)₂, —(CH₂)_(r)S(O)_(t)R¹⁴,             —(CH₂)_(r)-phenyl, or —(CH₂)_(r)N(H)C(O)—(C₁-C₃ alkyl);             -   R¹³ is H or C₁-C₃ alkyl; and             -   R¹⁴ is C₁-C₃ alkyl;             -   the subscript r is 1 or 2;             -   the subscript t is 0, 1, or 2;         -   R^(d) is H or C₁-C₃ alkyl; and             B is as set forth in any one embodiment nos. 1-3.

In embodiment no. 9, the invention provides a compound of the Formula (I), wherein A is as set forth in embodiment no. 8;

R^(a) is H or methoxymethyl;

R^(b) is H;

R^(c) is H, methyl, methoxymethyl, or —CH₂SO₂CH₃; and

R^(d) is H; and

B is as set forth in any one embodiment nos. 1-3.

In embodiment no. 10, the invention provides a compound of the Formula (I) wherein A is as set forth in embodiment no. 9, and B is as set forth in embodiment no. 3.

In embodiment no. 11, the invention provides a compound selected from any one of Examples 1-16 below.

In embodiment no. 12, the invention provides a compound selected from the group consisting of:

(S)-5-((2-aminopropyl)amino)-3-(benzofuran-2-yl)pyrazine-2-carboxamide;

5-(((1R,2S)-2-aminocyclohexyl)amino)-3-(1H-indol-2-yl)pyrazine-2-carboxamide;

5-{[(2S)-2-aminopropyl]amino}-3-(1H-indol-2-yl)pyrazine-2-carboxamide;

5-(((3S,4S)-4-amino-1,1-dioxidotetrahydro-2H-thiopyran-3-yl)amino)-3-(1H-indol-2-yl)pyrazine-2-carboxamide;

(S)-5-((2-aminopropyl)amino)-3-(5-bromo-1H-indol-2-yl)pyrazine-2-carboxamide;

(S)-5-((2-aminopropyl)amino)-3-(5-(1-methyl-1H-pyrazol-4-yl)-1H-indol-2-yl)pyrazine-2-carboxamide;

(S)-5-((2-aminopropyl)amino)-3-(5-(2-(2-oxopyrrolidin-1-yl)ethyl)-1H-indol-2-yl)pyrazine-2-carboxamide;

5-{[(1R,2S)-2-aminocyclohexyl]amino}-3-(5-chloro-1H-indol-2-yl)pyrazine-2-carboxamide;

5-{[(2S)-2-aminopropyl]amino}-3-(4-bromo-1H-indol-2-yl)pyrazine-2-carboxamide;

5-[(3-aminotetrahydro-2H-pyran-4-yl)amino]-3-(4-chloro-1H-indol-2-yl)pyrazine-2-carboxamide;

5-[(3-aminotetrahydro-2H-pyran-4-yl)amino]-3-(4-chloro-1H-indol-2-yl)pyrazine-2-carboxamide;

5-{[(3R,4R)-3-aminotetrahydro-2H-pyran-4-yl]amino}-3-(5-methoxy-1H-indol-2-yl)pyrazine-2-carboxamide;

5-{[(3R,4R)-3-aminotetrahydro-2H-pyran-4-yl]amino}-3-(6-fluoro-1H-indol-2-yl)pyrazine-2-carboxamide;

5-{[(3S,4S)-4-amino-1,1-dioxidotetrahydro-2H-thiopyran-3-yl]amino}-3-(4-chloro-1H-indol-2-yl)pyrazine-2-carboxamide;

5-{[(3S,4S)-4-amino-1,1-dioxidotetrahydro-2H-thiopyran-3-yl]amino}-3-(5-methoxy-1H-indol-2-yl)pyrazine-2-carboxamide;

5-{[(3S,4S)-4-amino-1,1-dioxidotetrahydro-2H-thiopyran-3-yl]amino}-3-(5-fluoro-1H-indol-2-yl)pyrazine-2-carboxamide;

5-{[(3S,4S)-4-amino-1,1-dioxidotetrahydro-2H-thiopyran-3-yl]amino}-3-(5-chloro-1H-indol-2-yl)pyrazine-2-carboxamide;

(R)-5-((2-amino-3-methoxypropyl)amino)-3-(1H-indol-2-yl)pyrazine-2-carboxamide;

5-{[(3R,4R)-4-amino-1,1-dioxidotetrahydro-2H-thiopyran-3-yl]amino}-3-(1H-indol-2-yl)pyrazine-2-carboxamide;

5-{[(1R,2S)-2-aminocyclohexyl]amino}-3-(4-methyl-1H-indol-2-yl)pyrazine-2-carboxamide;

5-{[(3R,4R)-3-aminotetrahydro-2H-pyran-4-yl]amino}-3-(4-methyl-1H-indol-2-yl)pyrazine-2-carboxamide;

5-{[(3R,4R)-3-aminotetrahydro-2H-pyran-4-yl]amino}-3-(4-methoxy-1H-indol-2-yl)pyrazine-2-carboxamide;

5-{[(3R,4R)-3-aminotetrahydro-2H-pyran-4-yl]amino}-3-(1H-indol-2-yl)pyrazine-2-carboxamide;

5-{[(2R)-2-amino-3-methoxypropyl]amino}-3-(4-methoxy-1H-indol-2-yl)pyrazine-2-carboxamide;

5-[(2-aminoethyl)amino]-3-(5-fluoro-1H-indol-2-yl)pyrazine-2-carboxamide;

5-(((3R,4R)-3-aminotetrahydro-2H-pyran-4-yl)amino)-3-(4-methoxy-1H-pyrrolo[2,3-c]pyridin-2-yl)pyrazine-2-carboxamide;

5-(((3S,4S)-4-amino-1,1-dioxidotetrahydro-2H-thiopyran-3-yl)amino)-3-(5-(trifluoromethyl)-1H-indol-2-yl)pyrazine-2-carboxamide;

5-{[(3R,4R)-3-aminotetrahydro-2H-pyran-4-yl]amino}-3-(2,3-dihydro-7H-[1,4]dioxino[2,3-e]indol-8-yl)pyrazine-2-carboxamide;

5-{[(3R,4R)-3-aminotetrahydro-2H-pyran-4-yl]amino}-3-(4,5-dimethoxy-1H-indol-2-yl)pyrazine-2-carboxamide;

5-{[(3R,4R)-3-aminotetrahydro-2H-pyran-4-yl]amino}-3-(5-ethyl-1H-indol-2-yl)pyrazine-2-carboxamide;

5-{[(3R,4R)-3-aminotetrahydro-2H-pyran-4-yl]amino}-3-(4-ethyl-1H-indol-2-yl)pyrazine-2-carboxamide;

5-{[(3R,4R)-3-aminotetrahydro-2H-pyran-4-yl]amino}-3-(1H-pyrrolo[3,2-c]pyridin-2-yl)pyrazine-2-carboxamide;

5-{[(3R,4R)-3-aminotetrahydro-2H-pyran-4-yl]amino}-3-(1H-pyrrolo[3,2-b]pyridin-2-yl)pyrazine-2-carboxamide;

5-{[(3R,4R)-3-aminotetrahydro-2H-pyran-4-yl]amino}-3-(1H-pyrrolo[2,3-c]pyridin-2-yl)pyrazine-2-carboxamide;

(S)-5-((2-aminopropyl)amino)-3-(phenylethynyl)pyrazine-2-carboxamide;

5-(((3S,4S)-4-amino-1,1-dioxidotetrahydro-2H-thiopyran-3-yl)amino)-3-(3-chloro-1H-indol-2-yl)pyrazine-2-carboxamide;

(2-(6-(((3S,4S)-4-amino-1,1-dioxidotetrahydro-2H-thiopyran-3-yl)amino)-3-carbamoylpyrazin-2-yl)-1H-indol-3-yl)dimethylsulfonium;

(S)-5-((2-aminopropyl)amino)-3-(5-(pyridin-3-yl)-1H-indol-2-yl)pyrazine-2-carboxamide;

5-(2-aminoethylamino)-3-(1H-indol-2-yl)pyrazine-2-carboxamide;

5-{[2-amino-3-(methylsulfonyl)propyl]amino}-3-(1H-indol-2-yl)pyrazine-2-carboxamide;

(R)-5-((1-amino-3-methoxypropan-2-yl)amino)-3-(1H-indol-2-yl)pyrazine-2-carboxamide; and

(S)-5-((1-amino-3-methoxypropan-2-yl)amino)-3-(1H-indol-2-yl)pyrazine-2-carboxamide;

or a pharmaceutically acceptable salt thereof.

In embodiment no. 13, the invention provides a compound selected from the group consisting of:

5-(((3S,4S)-4-amino-1,1-dioxidotetrahydro-2H-thiopyran-3-yl)amino)-3-(1H-indol-2-yl)pyrazine-2-carboxamide;

5-{[(3R,4R)-3-aminotetrahydro-2H-pyran-4-yl]amino}-3-(5-methoxy-1H-indol-2-yl)pyrazine-2-carboxamide;

5-{[(1R,2S)-2-aminocyclohexyl]amino}-3-(4-methyl-1H-indol-2-yl)pyrazine-2-carboxamide;

5-{[(3R,4R)-3-aminotetrahydro-2H-pyran-4-yl]amino}-3-(4-methoxy-1H-indol-2-yl)pyrazine-2-carboxamide; and

(S)-5-((2-aminopropyl)amino)-3-(5-(pyridin-3-yl)-1H-indol-2-yl)pyrazine-2-carboxamide;

or a pharmaceutically acceptable salt thereof.

The invention also provides a compound of Formula (I) or a pharmaceutically acceptable salt thereof in purified form.

Uses of the Compounds

Compounds of Formula (I) or its pharmaceutically acceptable salts and pharmaceutical compositions containing such compounds can be used to treat or prevent a variety of conditions or diseases mediated by Spleen tyrosine kinase (Syk). Such conditions and diseases include, but are not limited to: (1) arthritis, including rheumatoid arthritis, juvenile arthritis, psoriatic arthritis and osteoarthritis; (2) asthma and other obstructive airways diseases, including chronic asthma, late asthma, severe asthma, asthma exacerbations, airway hyper-responsiveness, bronchitis, bronchial asthma, allergic asthma, intrinsic asthma, extrinsic asthma, dust asthma, adult respiratory distress syndrome, recurrent airway obstruction, and chronic obstruction pulmonary disease including emphysema; (3) autoimmune diseases or disorders, including those designated as single organ or single cell-type autoimmune disorders, for example Hashimoto's thyroiditis, autoimmune hemolytic anemia, autoimmune atrophic gastritis of pernicious anemia, autoimmune encephalomyelitis, autoimmune orchitis, Goodpasture's disease, autoimmune thrombocytopenia including idiopathic thrombopenic purpura, sympathetic ophthalmia, myasthenia gravis, Graves' disease, primary biliary cirrhosis, chronic aggressive hepatitis, ulcerative colitis and membranous glomerulopathy, those designated as involving systemic autoimmune disorder, for example systemic lupus erythematosis, immune thrombocytopenic purpura, rheumatoid arthritis, Sjogren's syndrome, Reiter's syndrome, polymyositis-dermatomyositis, systemic sclerosis, polyarteritis nodosa, multiple sclerosis and bullous pemphigoid, and additional autoimmune diseases, which can be B-cell (humoral) based or T-cell based, including Cogan's syndrome, ankylosing spondylitis, Wegener's granulomatosis, autoimmune alopecia, Type I or juvenile onset diabetes, and thyroiditis; (4) cancers or tumors, including alimentary/gastrointestinal tract cancer, colon cancer, liver cancer, skin cancer including mast cell tumor and squamous cell carcinoma, breast and mammary cancer, ovarian cancer, prostate cancer, lymphoma and leukemia (including but not limited to acute myelogenous leukemia, chronic myelogenous leukemia, mantle cell lymphoma, NHL B cell lymphomas (e.g., precursor B-ALL, marginal zone B cell lymphoma, chronic lymphocytic leukemia, diffuse large B cell lymphoma, Burkitt lymphoma, mediastinal large B-cell lymphoma), Hodgkin lymphoma, NK and T cell lymphomas; TEL-Syk and ITK-Syk fusion driven tumors) myelomas including multiple myeloma, myeloproliferative disorders kidney cancer, lung cancer, muscle cancer, bone cancer, bladder cancer, brain cancer, melanoma including oral and metastatic melanoma, Kaposi's sarcoma, proliferative diabetic retinopathy, and angiogenic-associated disorders including solid tumors, and pancreatic cancer; (5) diabetes, including Type I diabetes and complications from diabetes; (6) eye diseases, disorders or conditions including autoimmune diseases of the eye, keratoconjunctivitis, vernal conjunctivitis, uveitis including uveitis associated with Behcet's disease and lens-induced uveitis, keratitis, herpetic keratitis, conical keratitis, corneal epithelial dystrophy, keratoleukoma, ocular premphigus, Mooren's ulcer, scleritis, Grave's ophthalmopathy, Vogt-Koyanagi-Harada syndrome, keratoconjunctivitis sicca (dry eye), phlyctenule, iridocyclitis, sarcoidosis, endocrine ophthalmopathy, sympathetic ophthalmitis, allergic conjunctivitis, and ocular neovascularization; (7) intestinal inflammations, allergies or conditions including Crohn's disease and/or ulcerative colitis, inflammatory bowel disease, coeliac diseases, proctitis, eosinophilic gastroenteritis, and mastocytosis; (8) neurodegenerative diseases including motor neuron disease, Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, Huntington's disease, cerebral ischemia, or neurodegenerative disease caused by traumatic injury, strike, glutamate neurotoxicity or hypoxia; ischemic/reperfusion injury in stroke, myocardial ischemica, renal ischemia, heart attacks, cardiac hypertrophy, atherosclerosis and arteriosclerosis, organ hypoxia; (9) platelet aggregation and diseases associated with or caused by platelet activation, such as arteriosclerosis, thrombosis, intimal hyperplasia and restenosis following vascular injury; (10) conditions associated with cardiovascular diseases, including restenosis, acute coronary syndrome, myocardial infarction, unstable angina, refractory angina, occlusive coronary thrombus occurring post-thrombolytic therapy or post-coronary angioplasty, a thrombotically mediated cerebrovascular syndrome, embolic stroke, thrombotic stroke, transient ischemic attacks, venous thrombosis, deep venous thrombosis, pulmonary embolus, coagulopathy, disseminated intravascular coagulation, thrombotic thrombocytopenic purpura, thromboangiitis obliterans, thrombotic disease associated with heparin-induced thrombocytopenia, thrombotic complications associated with extracorporeal circulation, thrombotic complications associated with instrumentation such as cardiac or other intravascular catheterization, intra-aortic balloon pump, coronary stent or cardiac valve, conditions requiring the fitting of prosthetic devices, and the like; (11) skin diseases, conditions or disorders including atopic dermatitis, eczema, psoriasis, scleroderma, pruritus and other pruritic conditions; (12) allergic reactions including anaphylaxis, allergic rhinitis, allergic dermatitis, allergic urticaria, angioedema, allergic asthma, or allergic reaction to insect bites, food, drugs, or pollen; (13) transplant rejection, including pancreas islet transplant rejection, bone marrow transplant rejection, graft-versus-host disease, organ and cell transplant rejection such as bone marrow, cartilage, cornea, heart, intervertebral disc, islet, kidney, limb, liver, lung, muscle, myoblast, nerve, pancreas, skin, small intestine, or trachea, and xeno transplantation; (14) low grade scarring including scleroderma, increased fibrosis, cystic fibrosis, keloids, post-surgical scars, pulmonary fibrosis, vascular spasms, migraine, reperfusion injury, and post-myocardial infarction.

The invention thus provides compounds of Formula (I) and pharmaceutically acceptable salts thereof for use in therapy, and particularly in the treatment of diseases and conditions mediated by inappropriate Syk activity. The inappropriate Syk activity referred to herein is any Syk activity that deviates from the normal Syk activity expected in a particular patient. Inappropriate Syk activity may take the form of, for instance, an abnormal increase in activity, or an aberration in the timing and or control of Syk activity. Such inappropriate activity may result then, for example, from overexpression or mutation of the protein kinase leading to inappropriate or uncontrolled activation.

In a further embodiment, the present invention is directed to methods of regulating, modulating, or inhibiting Syk for the prevention and/or treatment of disorders related to unregulated Syk activity.

In a further embodiment, the present invention provides a method of treatment of a patient suffering from a disorder mediated by Syk activity, which comprises administering to said patient an effective amount of a compound of Formula (I) or a pharmaceutically acceptable salt, solvate, or a physiologically functional derivative thereof. In a further embodiment, the present invention provides for the use of a compound of Formula (I), or a pharmaceutically acceptable salt or solvate thereof, or a physiologically functional derivative thereof, in the preparation of a medicament for the treatment of a disorder mediated by Syk activity.

In a further embodiment said disorder mediated by Syk activity is asthma. In a further embodiment said disorder is rheumatoid arthritis. In yet another embodiment, said disorder is cancer. In a further embodiment said disorder is ocular conjunctivitis.

Yet another aspect of the present invention provides a method for treating diseases caused by or associated with Fc receptor signaling cascades, including FceRI and/or FcgRI-mediated degranulation as a therapeutic approach towards the treatment or prevention of diseases characterized by, caused by and/or associated with the release or synthesis of chemical mediators of such Fc receptor signaling cascades or degranulation. In addition, Syk is known to play a critical role in immunotyrosine-based activation motif (ITAM) signaling, B cell receptor signaling, T cell receptor signaling and is an essential component of integrin beta (1), beta (2), and beta (3) signaling in neutrophils. Thus, compounds of the present invention can be used to regulate Fc receptor, ITAM, B cell receptor and integrin signaling cascades, as well as the cellular responses elicited through these signaling cascades. Non-limiting examples of cellular responses that may be regulated or inhibited include respiratory burst, cellular adhesion, cellular degranulation, cell spreading, cell migration, phagocytosis, calcium ion flux, platelet aggregation and cell maturation.

Compositions and Administration

While it is possible that, for use in therapy, a compound of Formula (I), as well as pharmaceutically acceptable salts thereof, may be administered as the raw chemical, it is possible to present the active ingredient as a pharmaceutical composition. Accordingly, the invention further provides a pharmaceutical composition, which comprises a compound of Formula (I) and pharmaceutically acceptable salts thereof, and a pharmaceutically acceptable carrier. The compounds of the Formula (I) and pharmaceutically acceptable salts thereof, are as described above. The carriers must be acceptable in the sense of being compatible with the other ingredients of the formulation and not deleterious to the recipient thereof. In accordance with another aspect of the invention there is also provided a process for the preparation of a pharmaceutical composition including admixing a compound of the Formula (I), or a pharmaceutically acceptable salt thereof, with one or more pharmaceutically acceptable carriers.

Pharmaceutical compositions of the present invention may be presented in unit dose forms containing a predetermined amount of active ingredient per unit dose. Such a unit may contain, for example, 5 μg to 1 g, preferably 1 mg to 700 mg, more preferably 5 mg to 100 mg of a compound of the Formula (I), depending on the condition being treated, the route of administration and the age, weight and condition of the patient. Such unit doses may therefore be administered more than once a day. Preferred unit dosage compositions are those containing a daily dose or sub-dose (for administration more than once a day), as herein above recited, or an appropriate fraction thereof, of an active ingredient. Furthermore, such pharmaceutical compositions may be prepared by any of the methods well known in the pharmacy art.

Pharmaceutical compositions of the present invention may be adapted for administration by any appropriate route, for example by the oral (including buccal or sublingual), rectal, topical, inhaled, nasal, ocular, or parenteral (including intravenous and intramuscular) route. Such compositions may be prepared by any method known in the art of pharmacy, for example by bringing into association the active ingredient with the carrier(s) or excipient(s). Dosage forms include tablets, troches, dispersions, suspensions, solutions, capsules, creams, ointments, aerosols, and the like.

In a further embodiment, the present invention provides a pharmaceutical composition adapted for administration by the oral route, for treating, for example, rheumatoid arthritis.

In a further embodiment, the present invention provides a pharmaceutical composition adapted for administration by the nasal route, for treating, for example, allergic rhinitis.

In a further embodiment, the present invention provides a pharmaceutical composition adapted for administration by the inhaled route, for treating, for example, asthma, COPD or ARDS.

In a further embodiment, the present invention provides a pharmaceutical composition adapted for administration by the ocular route, for treating, diseases of the eye, for example, conjunctivitis.

In a further embodiment, the present invention provides a pharmaceutical composition adapted for administration by the parenteral (including intravenous) route, for treating, for example, cancer.

Pharmaceutical compositions of the present invention which are adapted for oral administration may be presented as discrete units such as capsules or tablets; powders or granules; solutions or suspensions in aqueous or non-aqueous liquids; edible foams or whips; or oil-in-water liquid emulsions or water-in-oil liquid emulsions.

For instance, for oral administration in the form of a tablet or capsule, the active drug component can be combined with an oral, non-toxic pharmaceutically acceptable inert carrier such as ethanol, glycerol, water and the like. Powders are prepared by comminuting the compound to a suitable fine size and mixing with a similarly comminuted pharmaceutical carrier such as an edible carbohydrate, as, for example, starch or mannitol. Flavoring, preservative, dispersing and coloring agent can also be present.

Capsules are made by preparing a powder mixture, as described above, and filling formed gelatin sheaths. Glidants and lubricants such as colloidal silica, talc, magnesium stearate, calcium stearate or solid polyethylene glycol can be added to the powder mixture before the filling operation. A disintegrating or solubilizing agent such as agar-agar, calcium carbonate or sodium carbonate can also be added to improve the availability of the medicament when the capsule is ingested.

Moreover, when desired or necessary, suitable binders, lubricants, disintegrating agents and coloring agents can also be incorporated into the mixture. Suitable binders include starch, gelatin, natural sugars such as glucose or beta-lactose, corn sweeteners, natural and synthetic gums such as acacia, tragacanth or sodium alginate, carboxymethylcellulose, polyethylene glycol, waxes and the like. Lubricants used in these dosage forms include sodium oleate, sodium stearate, magnesium stearate, sodium benzoate, sodium acetate, sodium chloride and the like. Disintegrators include, without limitation, starch, methyl cellulose, agar, bentonite, xanthan gum and the like. Tablets are formulated, for example, by preparing a powder mixture, granulating or slugging, adding a lubricant and disintegrant and pressing into tablets. A powder mixture is prepared by mixing the compound, suitably comminuted, with a diluent or base as described above, and optionally, with a binder such as carboxymethylcellulose, an aliginate, gelatin, or polyvinyl pyrrolidone, a solution retardant such as paraffin, a resorption accelerator such as a quaternary salt and/or an absorption agent such as bentonite, kaolin or dicalcium phosphate. The powder mixture can be granulated by wetting with a binder such as syrup, starch paste, acadia mucilage or solutions of cellulosic or polymeric materials and forcing through a screen. As an alternative to granulating, the powder mixture can be run through the tablet machine and the result is imperfectly formed slugs broken into granules. The granules can be lubricated to prevent sticking to the tablet forming dies by means of the addition of stearic acid, a stearate salt, talc or mineral oil. The lubricated mixture is then compressed into tablets. The compounds of the present invention can also be combined with a free flowing inert carrier and compressed into tablets directly without going through the granulating or slugging steps. A clear or opaque protective coating consisting of a sealing coat of shellac, a coating of sugar or polymeric material and a polish coating of wax can be provided. Dyestuffs can be added to these coatings to distinguish different unit dosages.

Oral fluids such as solution, syrups and elixirs can be prepared in dosage unit form so that a given quantity contains a predetermined amount of the compound. Syrups can be prepared by dissolving the compound in a suitably flavored aqueous solution, while elixirs are prepared through the use of a non-toxic alcoholic vehicle. Suspensions can be formulated by dispersing the compound in a non-toxic vehicle. Solubilizers and emulsifiers such as ethoxylated isostearyl alcohols and polyoxy ethylene sorbitol ethers, preservatives, flavor additive such as peppermint oil or natural sweeteners or saccharin or other artificial sweeteners, and the like can also be added.

Where appropriate, dosage unit compositions for oral administration can be microencapsulated. The formulation can also be prepared to prolong or sustain the release, for example, by coating or embedding particulate material in polymers, wax or the like.

The compounds of Formula (I) and pharmaceutically acceptable salts thereof can also be administered in the form of liposome delivery systems, such as small unilamellar vesicles, large unilamellar vesicles and multilamellar vesicles. Liposomes can be formed from a variety of phospholipids, such as cholesterol, stearylamine or phosphatidylcholines.

The compounds of Formula (I) and pharmaceutically acceptable salts thereof may also be delivered by the use of monoclonal antibodies as individual carriers to which the compound molecules are coupled. The compounds may also be coupled with soluble polymers as targetable drug carriers. Such polymers can include polyvinylpyrrolidone, pyran copolymer, polyhydroxypropylmethacrylamide-phenol, polyhydroxyethylaspartamidephenol, or polyethyleneoxidepolylysine substituted with palmitoyl residues. Furthermore, the compounds may be coupled to a class of biodegradable polymers useful in achieving controlled release of a drug, for example, polylactic acid, polyepsilon caprolactone, polyhydroxy butyric acid, polyorthoesters, polyacetals, polydihydropyrans, polycyanoacrylates and cross-linked or amphipathic block copolymers of hydrogels.

Dosage forms for inhaled administration may conveniently be formulated as aerosols or dry powders.

For compositions suitable and/or adapted for inhaled administration, it is preferred that the compound or salt of Formula (I) is in a particle-size-reduced form, and more preferably the size-reduced form is obtained or obtainable by micronisation. The preferable particle size of the size-reduced (e.g., micronised) compound or salt or solvate is defined by a D50 value of about 0.5 to about 10 microns (for example as measured using laser diffraction).

Aerosol formulations, e.g., for inhaled administration, can comprise a solution or fine suspension of the active substance in a pharmaceutically acceptable aqueous or non-aqueous solvent. Aerosol formulations can be presented in single or multidose quantities in sterile form in a sealed container, which can take the form of a cartridge or refill for use with an atomising device or inhaler. Alternatively the sealed container may be a unitary dispensing device such as a single dose nasal inhaler or an aerosol dispenser fitted with a metering valve (metered dose inhaler) which is intended for disposal once the contents of the container have been exhausted.

Where the dosage form comprises an aerosol dispenser, it preferably contains a suitable propellant under pressure such as compressed air, carbon dioxide or an organic propellant such as a hydrofluorocarbon (HFC). Suitable HFC propellants include 1,1,1,2,3,3,3-heptafluoropropane and 1,1,1,2-tetrafluoroethane. The aerosol dosage forms can also take the form of a pump-atomiser. The pressurised aerosol may contain a solution or a suspension of the active compound. This may require the incorporation of additional excipients e.g., co-solvents and/or surfactants to improve the dispersion characteristics and homogeneity of suspension formulations. Solution formulations may also require the addition of co-solvents such as ethanol. Other excipient modifiers may also be incorporated to improve, for example, the stability and/or taste and/or fine particle mass characteristics (amount and/or profile) of the formulation.

For pharmaceutical compositions suitable and/or adapted for inhaled administration, it is preferred that the pharmaceutical composition is a dry powder inhalable composition. Such a composition can comprise a powder base such as lactose, glucose, trehalose, mannitol or starch, the compound of Formula (I) or salt or solvate thereof (preferably in particle-size-reduced form, e.g., in micronised form), and optionally a performance modifier such as L-leucine or another amino acid, and/or metals salts of stearic acid such as magnesium or calcium stearate. Preferably, the dry powder inhalable composition comprises a dry powder blend of lactose and the compound of Formula (I) or salt thereof. The lactose is preferably lactose hydrate e.g., lactose monohydrate and/or is preferably inhalation-grade and/or fine-grade lactose. Preferably, the particle size of the lactose is defined by 90% or more (by weight or by volume) of the lactose particles being less than 1000 microns (micrometres) (e.g., 10-1000 microns e.g., 30-1000 microns) in diameter, and/or 50% or more of the lactose particles being less than 500 microns (e.g., 10-500 microns) in diameter. More preferably, the particle size of the lactose is defined by 90% or more of the lactose particles being less than 300 microns (e.g., 10-300 microns e.g., 50-300 microns) in diameter, and/or 50% or more of the lactose particles being less than 100 microns in diameter. Optionally, the particle size of the lactose is defined by 90% or more of the lactose particles being less than 100-200 microns in diameter, and/or 50% or more of the lactose particles being less than 40-70 microns in diameter. It is preferable that about 3 to about 30% (e.g., about 10%) (by weight or by volume) of the particles are less than 50 microns or less than 20 microns in diameter. For example, without limitation, a suitable inhalation-grade lactose is E9334 lactose (10% fines) (Borculo Domo Ingredients, Hanzeplein 25, 8017 J D Zwolle, Netherlands).

Optionally, in particular for dry powder inhalable compositions, a pharmaceutical composition for inhaled administration can be incorporated into a plurality of sealed dose containers (e.g., containing the dry powder composition) mounted longitudinally in a strip or ribbon inside a suitable inhalation device. The container is rupturable or peel-openable on demand and the dose of e.g., the dry powder composition can be administered by inhalation via the device such as the DISKUS® device (GlaxoSmithKline). Other dry powder inhalers are well known to those of ordinary skill in the art, and many such devices are commercially available, with representative devices including Aerolizer® (Novartis), Airmax™ (IVAX), ClickHaler® (Innovata Biomed), Diskhaler® (GlaxoSmithKline), Accuhaler (GlaxoSmithKline), Easyhaler® (Orion Pharma), Eclipse™ (Aventis), FlowCaps® (Hovione), Handihaler® (Boehringer Ingelheim), Pulvinal® (Chiesi), Rotahaler® (GlaxoSmithKline), SkyeHaler™ or Certihaler™ (SkyePharma), Twisthaler (Schering Corporation), Turbuhaler® (AstraZeneca), Ultrahaler® (Aventis), and the like.

Dosage forms for ocular administration may be formulated as solutions or suspensions with excipients suitable for ophthalmic use.

Dosage forms for nasal administration may conveniently be formulated as aerosols, solutions, drops, gels or dry powders.

Pharmaceutical compositions adapted for administration by inhalation include fine particle dusts or mists, which may be generated by means of various types of metered, dose pressurised aerosols, nebulizers or insufflators.

For pharmaceutical compositions suitable and/or adapted for intranasal administration, the compound of Formula (I) or a pharmaceutically acceptable salt or solvate thereof may be formulated as a fluid formulation for delivery from a fluid dispenser. Such fluid dispensers may have, for example, a dispensing nozzle or dispensing orifice through which a metered dose of the fluid formulation is dispensed upon the application of a user-applied force to a pump mechanism of the fluid dispenser. Such fluid dispensers are generally provided with a reservoir of multiple metered doses of the fluid formulation, the doses being dispensable upon sequential pump actuations. The dispensing nozzle or orifice may be configured for insertion into the nostrils of the user for spray dispensing of the fluid formulation into the nasal cavity. A fluid dispenser of the aforementioned type is described and illustrated in WO-A-2005/044354, the entire content of which is hereby incorporated herein by reference. The dispenser has a housing which houses a fluid discharge device having a compression pump mounted on a container for containing a fluid formulation. The housing has at least one finger-operable side lever which is movable inwardly with respect to the housing to cam the container upwardly in the housing to cause the pump to compress and pump a metered dose of the formulation out of a pump stem through a nasal nozzle of the housing. A particularly preferred fluid dispenser is of the general type illustrated in FIGS. 30-40 of WO-A-2005/044354.

The following are examples of representative pharmaceutical dosage forms for the compounds of this invention:

Injectable Suspension (I.M.) mg/mL Compound of Formula (I) 10 Methylcellulose 5.0 Tween 80 0.5 Benzyl alcohol 9.0 Benzalkonium chloride 1.0 Water for injection to a total volume of 1 mL Tablet mg/tablet Compound of Formula (I) 25 Microcrystalline Cellulose 415 Providone 14.0 Pregelatinized Starch 43.5 Magnesium Stearate 2.5 500 Capsule mg/capsule Compound of Formula (I) 25 Lactose Powder 573.5 Magnesium Stearate 1.5 600 Aerosol Per canister Compound of Formula (I)   24 mg Lecithin, NF Liquid Concentrate  1.2 mg Trichlorofluoromethane, NF 4.025 gm Dichlorodifluoromethane, NF 12.15 gm

It will be appreciated that when the compound of the present invention is administered in combination with other therapeutic agents normally administered by the inhaled, intravenous, oral or intranasal route, that the resultant pharmaceutical composition may be administered by the same routes.

It should be understood that in addition to the ingredients particularly mentioned above, the compositions may include other agents conventional in the art having regard to the type of formulation in question, for example those suitable for oral administration may include flavouring agents.

A therapeutically effective amount of a compound of the present invention will depend upon a number of factors including, for example, the age and weight of the animal, the precise condition requiring treatment and its severity, the nature of the formulation, and the route of administration, and will ultimately be at the discretion of the attendant physician or veterinarian. However, an effective amount of a compound of Formula (I) for the treatment of diseases or conditions associated with inappropriate Syk activity, will generally be in the range of 5 μg to 100 mg/kg body weight of recipient (patient) per day and more usually in the range of 5 μg to 10 mg/kg body weight per day. This amount may be given in a single dose per day or more usually in a number (such as two, three, four, five or six) of sub-doses per day such that the total daily dose is the same. An effective amount of a salt or solvate, thereof, may be determined as a proportion of the effective amount of the compound of Formula (I) per se.

The compositions of the invention can further comprise one or more additional therapeutic agents, as discussed in further detail below. Accordingly, in one embodiment, the present invention provides compositions comprising: (i) a compound of Formula (I) or a pharmaceutically acceptable salt thereof; (ii) one or more additional therapeutic agents, that are not compounds of Formula (I); and (iii) a pharmaceutically acceptable carrier, wherein the amounts in the composition are together effective to treat one of the disease or conditions discussed above.

Combination Therapy

The compounds of Formula (I) or their pharmaceutically acceptable salts may be used in combination, either in a single formulation or co-administered as separate formulations with at least one additional therapeutic agent to treat or prevent the diseases and conditions described herein. For the treatment of the inflammatory diseases, rheumatoid arthritis, psoriasis, inflammatory bowel disease, COPD, asthma and allergic rhinititis, these additional therapeutic agents include, but are not limited to: (1) TNF-α inhibitors such as infliximab (Remicade®), etanercept (Enbrel®), adalimumab (Humira®), certolizumab pegol (Cimzia®), and golimumab (Simponi®); (2) non-selective COX-I/COX-2 inhibitors (such as piroxicam, diclofenac, propionic acids such as naproxen, flubiprofen, fenoprofen, ketoprofen and ibuprofen, fenamates such as mefenamic acid, indomethacin, sulindac, etodolac, azapropazone, pyrazolones such as phenylbutazone, salicylates such as aspirin); (3) COX-2 inhibitors (such as meloxicam, celecoxib, rofecoxib, valdecoxib and etoricoxib); (4) other agents for treatment of rheumatoid arthritis including methotrexate, leflunomide, sulfasalazine, azathioprine, cyclosporin, tacrolimus, penicillamine, bucillamine, actarit, mizoribine, lobenzarit, ciclesonide, hydroxychloroquine, d-penicillamine, aurothiomalate, auranofin or parenteral or oral gold, cyclophosphamide, Lymphostat-B, BAFF/APRIL inhibitors and CTLA-4-Ig or mimetics thereof; (5) leukotriene biosynthesis inhibitor, 5-lipoxygenase (5-LO) inhibitor or 5-lipoxygenase activating protein (FLAP) antagonist such as zileuton; (6) LTD4 receptor antagonist such as zafirlukast, montelukast and pranlukast; (7) PDE4 inhibitor such as roflumilast, cilomilast, AWD-12-281 (Elbion), and PD-168787 (Pfizer); (8) antihistaminic H1 receptor antagonists such as cetirizine, levocetirizine, loratadine, desloratadine, fexofenadine, astemizole, azelastine, levocabastine, olopatidine, methapyrilene and chlorpheniramine; (9) α1- and α2-adrenoceptor agonist vasoconstrictor sympathomimetic agent, such as propylhexedrine, phenylephrine, phenylpropanolamine, pseudoephedrine, naphazoline hydrochloride, oxymetazoline hydrochloride, tetrahydrozoline hydrochloride, xylometazoline hydrochloride, and ethylnorepinephrine hydrochloride; (10) anticholinergic agents such as ipratropium bromide, tiotropium bromide, oxitropium bromide, aclidinium bromide, glycopyrrolate, (R,R)-glycopyrrolate, pirenzepine, and telenzepine; (11) β-adrenoceptor agonists such as metaproterenol, isoproterenol, isoprenaline, albuterol, formoterol (particularly the fumarate salt), salmeterol (particularly the xinafoate salt), terbutaline, orciprenaline, bitolterol mesylate, fenoterol, and pirbuterol, or methylxanthanines including theophylline and aminophylline, sodium cromoglycate; (12) insulin-like growth factor type I (IGF-1) mimetic; (13) glucocorticosteroids, especially inhaled glucocorticoid with reduced systemic side effects, such as prednisone, prednisolone, flunisolide, triamcinolone acetonide, beclomethasone dipropionate, budesonide, fluticasone propionate, ciclesonide and mometasone furoate; (14) kinase inhibitors such as inhibitors of the Janus Kinases (JAK 1 and/or JAK2 and/or JAK 3 and/or TYK2) such as tofacitinib (Pfizer), baricitinib (Incyte), VX-509 (Vertex), ASP-015K (Astellas), GLPG0634 (Galapagos), SB-1578 (SBIO), and AC-430 (Ambit Biosciences); p38 MAPK and IKK2; (15) B-cell targeting biologics such as rituximab (Rituxan®); (16) selective costimulation modulators such as abatacept (Orencia); (17) interleukin inhibitors, such as IL-1 inhibitor anakinra (Kineret) and IL-6 inhibitor tocilizumab (Actemra).

The present invention also provides for so-called “triple combination” therapy, comprising a compound of Formula (I) or a pharmaceutically acceptable salt thereof together with beta₂-adrenoreceptor agonist and an anti-inflammatory corticosteroid. Preferably this combination is for treatment and/or prophylaxis of asthma, COPD or allergic rhinitis. The beta₂-adrenoreceptor agonist and/or the anti-inflammatory corticosteroid can be as described above and/or as described in WO 03/030939 A1. Representative examples of such a “triple” combination are a compound of Formula (I) or a pharmaceutically acceptable salt thereof in combination with the components of Advair® (salmeterol xinafoate and fluticasone propionate), Symbicort® (budesonide and formoterol fumarate), or Dulera® (mometasone furoate and formoterol fumarate).

For the treatment of cancer a compound of Formula (I) may be combined with an one or more additional therapeutic agents which are anticancer agents. Examples of such agents can be found in Cancer Principles and Practice of Oncology by V. T. Devita and S. Hellman (editors), 6th edition (Feb. 15, 2001), Lippincott Williams & Wilkins Publishers. A person of ordinary skill in the art would be able to discern which combinations of agents would be useful based on the particular characteristics of the drugs and the cancer involved. Such anticancer agents include, but are not limited to, the following: (1) an estrogen receptor modulator such as diethylstibestral, tamoxifen, raloxifene, idoxifene, LY353381, LY117081, toremifene, fluoxymestero, and SH646; (2) other hormonal agents including aromatase inhibitors (e.g., aminoglutethimide, tetrazole anastrozole, letrozole and exemestane), luteinizing hormone release hormone (LHRH) analogues, ketoconazole, goserelin acetate, leuprolide, megestrol acetate and mifepristone; (3) an androgen receptor modulator such as finasteride and other 5α-reductase inhibitors, nilutamide, flutamide, bicalutamide, liarozole, and abiraterone acetate; (4) a retinoid receptor modulator such as bexarotene, tretinoin, 13-cis-retinoic acid, 9-cis-retinoic acid, α-difluoromethylornithine, ILX23-7553, trans-N-(4′-hydroxyphenyl) retinamide, and N-4-carboxyphenyl retinamide; (5) an antiproliferative agent such as antisense RNA and DNA oligonucleotides such as G3139, ODN698, RVASKRAS, GEM231, and INX3001, and antimetabolites such as enocitabine, carmofur, tegafur, pentostatin, doxifluridine, trimetrexate, fludarabine, capecitabine, galocitabine, cytarabine ocfosfate, fosteabine sodium hydrate, raltitrexed, paltitrexid, emitefur, tiazofurin, decitabine, nolatrexed, pemetrexed, nelzarabine, 2′-deoxy-2′-methylidenecytidine, 2′-fluoromethylene-2′-deoxycytidine, N6-[4-deoxy-4-[N2-[2(E),4(E)-tetradecadienoyl]glycylamino]-L-glycero-B-L-manno-heptopyranosyl]adenine, aplidine, ecteinascidin, troxacitabine, aminopterin, 5-fluorouracil, floxuridine, methotrexate, leucovarin, hydroxyurea, thioguanine (6-TG), mercaptopurine (6-MP), cytarabine, pentostatin, fludarabine phosphate, cladribine (2-CDA), asparaginase, gemcitabine, alanosine, swainsonine, lometrexol, dexrazoxane, methioninase, and 3-aminopyridine-2-carboxaldehyde thiosemicarbazone; (6) a prenyl-protein transferase inhibitor including farnesyl-protein transferase (FPTase), geranylgeranyl-protein transferase type I (GGPTase-I), and geranylgeranyl-protein transferase type-II (GGPTase-II, also called Rab GGPTase); (7) an HMG-CoA reductase inhibitor such as lovastatin, simvastatin, pravastatin, atorvastatin, fluvastatin and rosuvastatin; (8) an angiogenesis inhibitor such as inhibitors of the tyrosine kinase receptors Flt-1 (VEGFR1) and Flk-1/KDR (VEGFR2), inhibitors of epidermal-derived, fibroblast-derived, or platelet derived growth factors, MMP (matrix metalloprotease) inhibitors, integrin blockers, interferon-α, interleukin-12, erythropoietin, granulocyte-CSF (filgrastin), granulocyte, macrophage-CSF (sargramostim), pentosan polysulfate, cyclooxygenase inhibitors, steroidal anti-inflammatories, carboxyamidotriazole, combretastatin A-4, squalamine, 6-O-chloroacetyl-carbonyl)-fumagillol, thalidomide, angiostatin, troponin-1, angiotensin II antagonists, heparin, carboxypeptidase U inhibitors, and antibodies to VEGF, endostatin, ukrain, ranpirnase, IM862, acetyldinanaline, 5-amino-1-[[3,5-dichloro-4-(4-chlorobenzoyl)phenyl]-methyl]-1H-1,2,3-triazole-4-carboxamide, CM101, squalamine, combretastatin, RPI4610, NX31838, sulfated mannopentaose phosphate, and 3-[(2,4-dimethylpyrrol-5-yl)methylene]-2-indolinone (SU5416); (9) PPAR-γ agonists, PPAR-δ agonists, thiazolidinediones (such as DRF2725, CS-011, troglitazone, rosiglitazone, and pioglitazone), fenofibrate, gemfibrozil, clofibrate, GW2570, SB219994, AR-H039242, JTT-501, MCC-555, GW2331, GW409544, NN2344, KRP297, NP0110, DRF4158, NN622, GI262570, PNU182716, DRF552926, 2-[(5,7-dipropyl-3-trifluoromethyl-1,2-benzisoxazol-6-yl)oxy]-2-methylpropionic acid (disclosed in U.S. Ser. No. 09/782,856), and (2R)-7-(3-(2-chloro-4-(4-fluorophenoxy)phenoxy)propoxy)-2-ethylchromane-2-carboxylic acid (disclosed in U.S. Ser. No. 60/235,708 and 60/244,697); (9) an inhibitor of inherent multidrug resistance including inhibitors of p-glycoprotein (P-gp), such as LY335979, XR9576, OC144-093, R101922, VX853 and PSC833 (valspodar); (10) an inhibitor of cell proliferation and survival signaling such as inhibitors of EGFR (for example gefitinib and erlotinib), inhibitors of ERB-2 (for example trastuzumab), inhibitors of IGF 1R such as MK-0646 (dalotuzumab), inhibitors of CD20 (rituximab), inhibitors of cytokine receptors, inhibitors of MET, inhibitors of PI3K family kinase (for example LY294002), serine/threonine kinases (including but not limited to inhibitors of Akt such as described in (WO 03/086404, WO 03/086403, WO 03/086394, WO 03/086279, WO 02/083675, WO 02/083139, WO 02/083140 and WO 02/083138), inhibitors of Raf kinase (for example BAY-43-9006), inhibitors of MEK (for example CI-1040 and PD-098059) and inhibitors of mTOR (for example Wyeth CCI-779 and Ariad AP23573); (11) a bisphosphonate such as etidronate, pamidronate, alendronate, risedronate, zoledronate, ibandronate, incadronate or cimadronate, clodronate, EB-1053, minodronate, neridronate, piridronate and tiludronate; (12) γ-secretase inhibitors, (13) agents that interfere with receptor tyrosine kinases (RTKs) including inhibitors of c-Kit, Eph, PDGF, Flt3 and c-Met; (14) an agent that interferes with a cell cycle checkpoint including inhibitors of ATR, ATM, the Chk1 and Chk2 kinases and cdk and cdc kinase inhibitors and are specifically exemplified by 7-hydroxystaurosporin, flavopiridol, CYC202 (Cyclacel) and BMS-387032; (15) BTK inhibitors such as PCI32765, AVL-292 and AVL-101; (16) PARP inhibitors including iniparib, olaparib, AGO14699, ABT888 and MK4827; (16) ERK inhibitors; (17) mTOR inhibitors such as sirolimus, ridaforolimus, temsirolimus, everolimus; and (18) cytotoxic/cytostatic agents.

“Cytotoxic/cytostatic agents” refer to compounds which cause cell death or inhibit cell proliferation primarily by interfering directly with the cell's functioning or inhibit or interfere with cell mytosis, including alkylating agents, tumor necrosis factors, intercalators, hypoxia activatable compounds, microtubule inhibitors/microtubule-stabilizing agents, inhibitors of mitotic kinesins, inhibitors of histone deacetylase, inhibitors of kinases involved in mitotic progression, antimetabolites; biological response modifiers; hormonal/anti-hormonal therapeutic agents, haematopoietic growth factors, monoclonal antibody targeted therapeutic agents, topoisomerase inhibitors, proteasome inhibitors and ubiquitin ligase inhibitors.

Examples of cytotoxic agents include, but are not limited to, sertenef, cachectin, chlorambucil, cyclophosphamide, ifosfamide, mechlorethamine, melphalan, uracil mustard, thiotepa, busulfan, carmustine, lomustine, streptozocin, tasonermin, lonidamine, carboplatin, altretamine, dacarbazine, procarbazine, prednimustine, dibromodulcitol, ranimustine, fotemustine, nedaplatin, oxaliplatin, temozolomide, heptaplatin, estramustine, improsulfan tosilate, trofosfamide, nimustine, dibrospidium chloride, pumitepa, lobaplatin, satraplatin, profiromycin, cisplatin, irofulven, dexifosfamide, cis-aminedichloro(2-methyl-pyridine)platinum, benzylguanine, glufosfamide, GPX100, (trans, trans, trans)-bis-mu-(hexane-1,6-diamine)-mu-[diamine-platinum(II)]bis[diamine(chloro)platinum (II)]tetrachloride, diarizidinylspermine, arsenic trioxide, 1-(11-dodecylamino-10-hydroxyundecyl)-3,7-dimethylxanthine, zorubicin, doxorubicin, daunorubicin, idarubicin, anthracenedione, bleomycin, mitomycin C, dactinomycin, plicatomycin, bisantrene, mitoxantrone, pirarubicin, pinafide, valrubicin, amrubicin, antineoplaston, 3′-deamino-3′-morpholino-13-deoxo-10-hydroxycarminomycin, annamycin, galarubicin, elinafide, MEN10755, and 4-demethoxy-3-deamino-3-aziridinyl-4-methylsulphonyl-daunorubicin.

An example of a hypoxia activatable compound is tirapazamine.

Examples of proteasome inhibitors include but are not limited to lactacystin and bortezomib.

Examples of microtubule inhibitors/microtubule-stabilising agents include vincristine, vinblastine, vindesine, vinzolidine, vinorelbine, vindesine sulfate, 3′,4′-didehydro-4′-deoxy-8′-norvincaleukoblastine, podophyllotoxins (e.g., etoposide (VP-16) and teniposide (VM-26)), paclitaxel, docetaxol, rhizoxin, dolastatin, mivobulin isethionate, auristatin, cemadotin, RPR109881, BMS184476, vinflunine, cryptophycin, anhydrovinblastine, N,N-dimethyl-L-valyl-L-valyl-N-methyl-L-valyl-L-prolyl-L-proline-t-butylamide, TDX258, the epothilones (see for example U.S. Pat. Nos. 6,284,781 and 6,288,237) and BMS188797.

Some examples of topoisomerase inhibitors are topotecan, hycaptamine, irinotecan, rubitecan, 6-ethoxypropionyl-3′,4′-O-exo-benzylidene-chartreusin, lurtotecan, 7-[2-(N-isopropylamino)ethyl]-(20S)camptothecin, BNP1350, BNPI1100, BN80915, BN80942, etoposide phosphate, teniposide, sobuzoxane, 2′-dimethylamino-2′-deoxy-etoposide, GL331, N-[2-(dimethylamino)ethyl]-9-hydroxy-5,6-dimethyl-6H-pyrido[4,3-b]carbazole-1-carboxamide, asulacrine, 2,3-(methylenedioxy)-5-methyl-7-hydroxy-8-methoxybenzo[c]-phenanthridinium, 5-(3-aminopropylamino)-7,10-dihydroxy-2-(2-hydroxyethylaminomethyl)-6H-pyrazolo[4,5,1-de]acridin-6-one, N-[1-[2-(diethylamino)ethylamino]-7-methoxy-9-oxo-9H-thioxanthen-4-ylmethyl]formamide, N-(2-(dimethylamino)ethyl)acridine-4-carboxamide, 6-[[2-(dimethylamino)ethyl]amino]-3-hydroxy-7H-indeno[2,1-c]quinolin-7-one, and dimesna.

Examples of inhibitors of mitotic kinesins include, but are not limited to inhibitors of KSP, inhibitors of MKLP1, inhibitors of CENP-E, inhibitors of MCAK, inhibitors of Kif14, inhibitors of Mphosphl and inhibitors of Rab6-KIFL.

Examples of “histone deacetylase inhibitors” include, but are not limited to, vorinostat, trichostatin A, oxamflatin, PXD101, MG98, valproic acid and scriptaid.

“Inhibitors of kinases involved in mitotic progression” include, but are not limited to, inhibitors of aurora kinase, inhibitors of Polo-like kinases (PLK; in particular inhibitors of PLK-1), inhibitors of bub-1 and inhibitors of bub-R1. An example of an “aurora kinase inhibitor” is VX-680.

“Antiproliferative agents” includes antisense RNA and DNA oligonucleotides such as G3139, ODN698, RVASKRAS, GEM231, and INX3001, and antimetabolites such as enocitabine, carmofur, tegafur, pentostatin, doxifluridine, trimetrexate, fludarabine, capecitabine, galocitabine, cytarabine ocfosfate, fosteabine sodium hydrate, raltitrexed, paltitrexid, emitefur, tiazofurin, decitabine, nolatrexed, pemetrexed, nelzarabine, 2′-deoxy-2′-methylidenecytidine, 2′-fluoromethylene-2′-deoxycytidine, N6-[4-deoxy-4-[N2-[2,4-tetradecadienoyl]glycylamino]-L-glycero-B-L-manno-heptopyranosyl]adenine, aplidine, ecteinascidin, troxacitabine, aminopterin, 5-fluorouracil, floxuridine, methotrexate, leucovarin, hydroxyurea, thioguanine (6-TG), mercaptopurine (6-MP), cytarabine, pentostatin, fludarabine phosphate, cladribine (2-CDA), asparaginase, gemcitabine, alanosine, swainsonine, lometrexol, dexrazoxane, methioninase, and 3-aminopyridine-2-carboxaldehyde thiosemicarbazone.

Non-limiting examples of suitable additional therapeutic agents used in cancer therapy that may be combined with compounds of Formula (I) include, but are not limited to, abarelix; aldesleukin; alemtuzumab; alitretinoin; allopurinol; altretamine; amifostine; anastrozole; arsenic trioxide; asparaginase; azacitidine; bendamustine; bevacuzimab; bexarotene; bleomycin; bortezomib; busulfan; calusterone; capecitabine; carboplatin; carmustine; cetuximab; chlorambucil; cisplatin; cladribine; clofarabine; cyclophosphamide; cytarabine; dacarbazine; dactinomycin, actinomycin D; dalteparin; darbepoetin alfa; dasatinib; daunorubicin; degarelix; denileukin diftitox; dexrazoxane; docetaxel; doxorubicin; dromostanolone propionate; eculizumab; Elliott's B Solution; eltrombopag; epirubicin; epoetin alfa; erlotinib; estramustine; etoposide phosphate; etoposide; everolimus; exemestane; filgrastim; floxuridine; fludarabine; fluorouracil; fulvestrant; gefitinib; gemcitabine; gemtuzumab ozogamicin; goserelin acetate; histrelin acetate; hydroxyurea; ibritumomab tiuxetan; idarubicin; ifosfamide; imatinib mesylate; interferon alfa 2a; interferon alfa-2b; irinotecan; ixabepilone; lapatinib; lenalidomide; letrozole; leucovorin; leuprolide acetate; levamisole; lomustine; meclorethamine, nitrogen mustard; megestrol acetate; melphalan, L-PAM; mercaptopurine; mesna; methotrexate; methoxsalen; mitomycin C; mitotane; mitoxantrone; nandrolone phenpropionate; nelarabine; nilotinib; Nofetumomab; ofatumumab; oprelvekin; oxaliplatin; paclitaxel; palifermin; pamidronat; panitumumab; pazopanib; pegademase; pegaspargase; Pegfilgrastim; pemetrexed disodium; pentostatin; pipobroman; plerixafor; plicamycin, mithramycin); porfimer sodium; pralatrexate; procarbazine; quinacrine; Rasburicase; raloxifene hydrochloride; Rituximab; romidepsin; romiplostim; sargramostim; sargramostim; satraplatin; sorafenib; streptozocin; sunitinib maleate; tamoxifen; temozolomide; temsirolimus; teniposide; testolactone; thioguanine; thiotepa; topotecan; toremifene; tositumomab; trastuzumab; tretinoin; uracil mustard; valrubicin; vinblastine; vincristine; vinorelbine; vorinostat; and zoledronate.

When administering a combination therapy to a patient in need of such administration, the therapeutic agents in the combination, or a pharmaceutical composition or compositions comprising the therapeutic agents, may be administered in any order such as, for example, sequentially, concurrently, together, simultaneously and the like.

These combinations are of particular interest in respiratory diseases and are conveniently adapted for inhaled or intranasal delivery.

In one embodiment, the compound of Formula (I) is administered during a time when the additional therapeutic agent(s) exert their prophylactic or therapeutic effect, or vice versa.

In another embodiment, the compound of Formula (I) and the additional therapeutic agent(s) are administered in doses commonly employed when such agents are used as monotherapy for treating the disorder.

In another embodiment, the compound of Formula (I) and the additional therapeutic agent(s) are administered in doses lower than the doses commonly employed when such agents are used as monotherapy for treating the disorder.

In one embodiment, the compound of Formula (I) and the additional therapeutic agent(s) are present in the same composition, which is suitable for oral administration.

The compound of Formula (I) and the additional therapeutic agent(s) can act additively or synergistically. A synergistic combination may allow the use of lower dosages of one or more agents and/or less frequent administration of one or more agents of a combination therapy. A lower dosage or less frequent administration of one or more agents may lower toxicity of the therapy without reducing the efficacy of the therapy.

The doses and dosage regimen of the additional therapeutic agent(s) used in the combination therapies of the present invention for the treatment or prevention of a disease or disorder can be determined by the attending clinician, taking into consideration the approved doses and dosage regimen in the package insert; the age, sex and general health of the patient; and the type and severity of the disease or condition mediated by Syk.

Another aspect of this invention is a kit comprising a therapeutically effective amount of the compound of Formula (I) or a pharmaceutically acceptable salt of said compound, optionally at least one additional therapeutic agent listed above and a pharmaceutically acceptable carrier, vehicle or diluent.

Methods of Preparing the Compounds of Formula (I)

The compounds of this invention may be made by a variety of methods, including standard chemistry. Any previously defined variable will continue to have the previously defined meaning unless otherwise indicated. Illustrative general synthetic methods are set out below and then specific compounds of the Formula (I) are prepared in the Examples.

Compounds of general Formula (I) may be prepared by methods known in the art of organic synthesis as set forth in part by the following synthesis schemes. In all of the schemes described below, it is well understood that protecting groups for sensitive or reactive groups are employed where necessary in accordance with general principles of chemistry. Protecting groups are manipulated according to standard methods of organic synthesis (T. W. Green and P. G. M. Wuts (1991) Protecting Groups in Organic Synthesis, John Wiley & Sons). These groups are removed at a convenient stage of the compound synthesis using methods that are readily apparent to those skilled in the art. The selection of protecting groups as well as the reaction conditions and order of reaction steps shall be consistent with the preparation of compounds of Formula (I). Those skilled in the art will recognize whether a stereocenter exists in compounds of Formula (I). Accordingly, the present invention includes all possible stereoisomers and includes not only mixtures of stereoisomers (such as racemic compounds) but the individual stereoisomers as well. When a compound is desired as a single enantiomer, it may be obtained by stereospecific synthesis or by resolution of the final product or any convenient intermediate. Resolution of the final product, an intermediate, or a starting material may be affected by any suitable method known in the art. See, for example, Stereochemistry of Organic Compounds by E. L. Eliel, S. H. Wilen, and L. N. Mander (Wiley-Interscience, 1994).

The following solvents, reagents, protecting groups, moieties, and other designations may be referred to by their abbreviations:

Me=methyl; Et=ethyl; Pr=propyl; iPr=isopropyl, Bu=butyl; t-Bu=tert-butyl; Ph=phenyl, and Ac=acetyl

μl=microliters

AcOH or HOAc=acetic acid

ACN=acetonitrile

APCI=atmospheric-pressure chemical ionization

aq=aqueous

Bn=benzyl

Boc or BOC=tert-butoxycarbonyl

Bz=benzoyl

Boc=tert-butoxycarbonyl

Calc'd=calculated

Cbz=benyzloxycarbonyl

DCM=dichloromethane:

DMAP=4-dimethylaminopyridine

DIBAL=diisobutylaluminum hydride

DIEA or Hünig's Base=N,N-diisopropylethylamine

DMA=1,2-dimethylacetamide

DMF=dimethylformamide

DMSO=dimethyl sulfoxide

DTT=dithiothreitol

EDC=1-ethyl-3-(3-dimethylaminopropyl)carbodiimide

EDTA=ethylenediamine tetraacetic acid

ESI=electrospray ionization

EtOAc=ethyl acetate

g=grams

GST=glutathione S-transferase

h=hour

HMDS=1,1,1,3,3,3-hexamethyldisilazane

HATU=N,N,N′,N′-tetramethyl-O-(7-azabenzotriazol-1-yl)uronium hexafluorophosphate

HPLC=high-performance liquid chromatography

HOBt=1-hydroxybenzotriazole

LDA=lithium diisopropylamide

LCMS=liquid chromatography mass spectrometry

min=minute

mg=milligrams

mL=milliliters

mmol=millimoles

MeOH: methanol

MS=mass spectrometry

NBS=N-bromosuccimide

NMR=nuclear magnetic resonance spectroscopy

Obsv'd=observed

rac=racemic mixture

RT or rt=room temperature (ambient, about 25° C.)

sat=saturated

SFC=supercritical fluid chromatography

TBSC1=t-butyldimethylsilyl chloride

TBS=t-butyldimethyl silyl

TEA=triethylamine (Et₃N)

TFA=trifluoroacetic acid

TFAA=trifluoroacetic anhydride

THF=tetrahydrofuran

TLC=thin layer chromatography

TMS=trimethylsilyl

Tris=tris(hydroxymethyl)aminomethane

General Methods

Compounds of the Formula (I) can be prepared according to one of the general synthetic schemes procedures set forth in Schemes 1 and 2 below, and/or by methods similar to those described in the Examples below.

As shown in Scheme 1, compounds of Structural subtype (A) are prepared from substituted pyrazine-2-carbonitriles (A7) by either (a) hydrolysis of the nitrile, (b) acidic deprotection of the amino protecting groups followed by hydrolysis of the nitrile, or (c) hydrolysis of the nitrile followed by acidic deprotection of the amino protecting group. Substituted pyrazine-2-carbonitriles (A7) are prepared by a Suzuki reaction between (A6) with the appropriate boronic acid, boronate ester or trifluoroborate salt. Substituted 3-chloropyrazine-2-carbonitrile (A6) can be prepared via S_(n)Ar reaction with 3,5-dichloropyrazine-2-carbonitrile (A5) with the appropriately substituted amine (A2). Alternatively, (A6) can be prepared via a three step process starting with dichloropyrazine (A1). Dichloropyrazine (A1) is reacted via an S_(n)Ar reaction with substituted amine (A2) to form (A3). Iodination affords the di-halo compound which can be used in a Negishi coupling to form (A6).

Compounds of structural subtype (B) are prepared from the substituted carbonitrile (B1) by hydrolysis of the nitrile followed by acidic deprotection of the amino protecting groups. Sonogashira reaction between chloro-pyrazine-carbonitrile (A6) and the appropriate alkyne can be used to prepare (B1).

As shown in Scheme 2, compounds of structural subtype (C) can be formed via a Suzuki reaction between aryl bromide (C1) and the appropriate boron species.

The starting materials and reagents used in preparing compounds described in the examples below are either available from commercial suppliers or were prepared by literature methods known to those skilled in the art. For example, other A moiety precursors can be prepared using the published procedures which are specified below.

Tert-butyl (1R,2R)-2-amino-3,3-difluorocyclohexylcarbamate can be prepared according to the procedures described at pages 51-54 in International Patent Application Publication No. WO 2010/017046. Similarly, the enantiomer, tert-butyl (1S,2S)-2-amino-3,3-difluorocyclohexylcarbamate can be prepared analogously.

Tert-butyl rel-(3S,4S)-3-amino-1,1-dioxohexahydro-1-thiopyran-4-ylcarbamate (mixture of cis isomers) and tert-butyl rel-(3R,4S)-3-amino-1,1-dioxohexahydro-1-thiopyran-4-ylcarbamate (mixture of trans isomers) were prepared according to the procedures described in Referential Example No. 179 at page 92 of U.S. Patent Application Publication No. 2005/0020645.

(R)-tert-butyl 1-amino-3-methoxypropan-2-ylcarbamate was prepared according to the procedure described in Preparation 32 at page 87 of U.S. Patent Application Publication No. 2011/0152273. (S)-tert-butyl 1-amino-3-methoxypropan-2-ylcarbamate was prepared according to the procedures described at page 37 in International Patent Application Publication No. WO 2009/136995.

Benzyl tert-butyl (3-hydroxypropane-1,2-diyl)biscarbamate can be prepared according to the procedure described at pages 37-38 in International Patent Application Publication No. WO 2006/123020.

Tert-butyl [(3R,4R)-4-aminotetrahydro-2H-pyran-3-yl]carbamate can be prepared according to the procedures described at pages 32-39 of International Patent Application Publication No. WO 2010/097248.

Tert-butyl [(1S,2R)-2-aminocyclohexyl]carbamate is commerically available from Small Molecules, Inc.; CAS: 365996-30-1.

Additional A moiety precursors can be prepared according to the procedures described on pages 76-97 of International Patent Application Publication No. WO2013/052394.

The examples below are being provided to further illustrate the present invention. The examples provided below are for illustrative purposes only; the scope of the invention is not to be considered limited in any way thereby.

Where mass spectral (MS) data are presented in the examples below, analysis was performed using an Agilent Technologies 6120 quadrupole LC/MS. Resolution of enantiomers was typically performed using supercritical fluid chromatography utilizing a Chiral Technologies stationary phase such as OJ-H or OJ column (stationary phase with particle size of 5 or 10 micron) with a mobile phase of CO₂ and a lower alcohol such as methanol or isopropanol.

EXAMPLES Preparative Example 1 Preparation of 5-Cyanopyrazine Precursors Preparative Example 1.1 (R)-tert-butyl (1-((6-chloro-5-cyanopyrazin-2-yl)amino)-3-methoxypropan-2-yl)carbamate

Step 1: To a microwave vial containing 2,6-dichloropyrazine (1.114 g, 7.48 mmol) and (R)-tert-butyl (1-amino-3-methoxypropan-2-yl)carbamate, oxalate salt (2.00 g, 6.80 mmol) was added NMP (5.07 mL) and DIEA (5.93 ml, 34.0 mmol). The vial was capped and heated to 130° C. overnight. The reaction was allowed to cool to room temperature and then diluted with ethyl acetate and water. The organic layer was separated, dried over magnesium sulfate, filtered and concentrated under reduced pressure. The residue was purified by column chromatography on silica gel to afford (R)-tert-butyl (1-((6-chloropyrazin-2-yl)amino)-3-methoxypropan-2-yl)carbamate. MS ESI calcd. for C₉H₁₄ClN₄O₃ [M−C₄H₉+2H]+ 261, found 261. 1H NMR (500 MHz, DMSO-d6) δ 7.89 (s, 1H), 7.67 (s, 1H), 7.52 (s, 1H), 6.72 (d, J=7.8 Hz, 1H), 3.83-3.73 (m, 1H), 3.44-3.35 (m, 1H), 3.31-3.27 (m, 2H), 3.24 (s, 3H), 3.22-3.13 (m, 1H), 1.34 (s, 9H).

Step 2: To a mixture of (R)-tert-butyl (1-((6-chloropyrazin-2-yl)amino)-3-methoxypropan-2-yl)carbamate (1.36 g, 4.29 mmol) in DMF (10.73 ml) was added NIS (1.16 g, 5.15 mmol) and the mixture was heated to 80° C. overnight. The reaction was allowed to cool to room temperature and then diluted with ethyl acetate and water. The organic layer was separated, dried over magnesium sulfate, filtered and concentrated under reduced pressure. The residue was purified by column chromatography on silica gel to afford (R)-tert-butyl (1-((6-chloro-5-iodopyrazin-2-yl)amino)-3-methoxypropan-2-yl)carbamate. MS ESI calcd. for C₉H₁₃ClIN₄O₃ [M−C₄H₉+2H]⁺ 387, found 387. ¹H NMR (500 MHz, DMSO-d₆) δ 7.76 (s, 1H), 7.65 (s, 1H), 6.70 (d, J=8.7 Hz, 1H), 3.82-3.72 (m, 1H), 3.39-3.35 (m, 1H), 3.30-3.26 (m, 2H), 3.23 (s, 3H), 3.19-3.10 (m, 1H), 1.34 (s, 9H).

Step 3: To a mixture of (R)-tert-butyl (1-((6-chloro-5-iodopyrazin-2-yl)amino)-3-methoxypropan-2-yl)carbamate (1.037 g, 2.343 mmol) in DMF (12 ml) was added tetrakis(triphenylphosphine)palladium(0) (0.271 g, 0.234 mmol) and zinc cyanide (0.289 g, 2.46 mmol). The vial was capped and argon was bubbled through the solution for five minutes. The mixture was then placed in a reaction block that had been pre-heated to 120° C. After 30 minutes, the reaction was allowed to cool to room temperature and then diluted with ethyl acetate and water. The organic layer was separated, dried over magnesium sulfate, filtered and concentrated under reduced pressure. The residue was purified by column chromatography to afford (R)-tert-butyl (1-((6-chloro-5-cyanopyrazin-2-yl)amino)-3-methoxypropan-2-yl)carbamate. MS ESI calcd. for C₁₄H₂₀ClN₅O₃Na [M+Na]⁺ 364, found 364. ¹H NMR (500 MHz, DMSO-d6) δ 8.72 (s, 1H), 7.94 (s, 1H), 6.78 (d, J=8.9 Hz, 1H), 3.82 (d, J=5.1 Hz, 1H), 3.55-3.45 (m, 1H), 3.33 (s, 3H), 3.31-3.27 (m, 3H), 1.32 (s, 9H).

The intermediates in the following table were prepared according to the method described for Intermediate 3.

Prep- Ex. Exact No. Structure Name Mass Obsv'd 1.2

(S)-tert-butyl (1-((6-chloro- 5-cyanopyrazin-2- yl)amino)propan-2- yl)carbamate [M − C₄H₉ + 2H]⁺ = 256 [M − C₄H₉ + 2H]⁺ = 256 1.3

tert-butyl ((3S,4S)-3-((6- chloro-5-cyanopyrazin-2- yl)amino)-1,1- dioxidotetrahydro-2H- thiopyran-4-yl)carbamate [M + H]⁺ = 402 [M + H]⁺ = 402 1.4

tert-butyl (2-((6-chloro-5- cyanopyrazin-2- yl)amino)ethyl)carbamate [M − C₄H₉ + 2H]⁺ = 242 [M − C₄H₉ + 2H]⁺ = 242 1.5

tert-butyl (1-((6-chloro-5- cyanopyrazin-2-yl)amino)- 4-(methylsulfonyl)butan-2- yl)carbamate [M + Na]⁺ = 426 [M + Na]⁺ = 426 1.6

(S)-tert-butyl (1-((6-chloro- 5-cyanopyrazin-2- yl)amino)-3- methoxypropan-2- yl)carbamate [M + Na] = 364 [M + Na] = 364

Example 1 Example 1.1 (S)-5-((2-Aminopropyl)amino)-3-(benzofuran-2-yl)pyrazine-2-carboxamide

To a 5-mL microwave vial was added (S)-tert-butyl (1-((6-chloro-5-cyanopyrazin-2-yl)amino)propan-2-yl)carbamate (62 mg, 0.20 mmol), benzofuran-2-ylboronic acid (65 mg, 0.40 mmol), SiliaCat Si-DPP-Pd (0.38 mmol/g, 79 mg, 0.030 mmol), Na₂CO₃ (85 mg, 0.80 mmol), water (0.4 ml) and dioxane (1 mL). The mixture was irradiated in the microwave at 150° C. for 5 minutes. Upon cooling to room temperature, benzofuran-2-ylboronic acid (32 mg, 0.20 mmol) was added and the mixture was irradiated in the microwave at 150° C. for 5 minutes. Upon cooling to room temperature, the mixture was diluted with THF, filtered and the mixture was concentratd under reduced pressure. TFA (3 mL) was added and the mixture was concentrated under reduced pressure. To the residue was added DMSO (1.0 mL) and aqueous NaOH (10.0 M, 0.20 ml, 2.0 mmol). Hydrogen peroxide (35% in H₂O, 0.18 mL, 2.0 mmol) was added dropwise. Upon completion, MeOH (1 mL) was added and the mixture was filtered. The filtrate was purified via mass directed reverse phase HPLC to afford (S)-5-((2-aminopropyl)amino)-3-(benzofuran-2-yl)pyrazine-2-carboxamide as the TFA salt. MS ESI calcd. for C₁₆H₁₈N₅O₂ [M+H]⁺ 312, found 312. ¹H NMR (500 MHz, DMSO): δ 7.93 (s, 1 H); 7.87 (s, 3 H); 7.81-7.80 (m, 2 H); 7.71 (d, J=7.7 Hz, 1 H); 7.56-7.54 (m, 1 H); 7.45 (s, 1 H); 7.44 (d, J=1.0 Hz, 1 H); 7.37-7.34 (m, 1 H); 7.30-7.28 (m, 1 H); 3.52-3.51 (m, 3 H); 1.23 (d, J=6.1 Hz, 3 H).

Example 2 Example 2.1 5-((1R,2S)-2-Aminocyclohexyl)amino)-3-(1H-indol-2-yl)pyrazine-2-carboxamide

Step 1: To a flask containing tert-butyl ((1S,2R)-2-((6-chloro-5-cyanopyrazin-2-yl)amino)cyclohexyl)carbamate (100 mg, 0.28 mmol), 1H-indole-2-boronic acid pinacol ester (138 mg, 0.568 mmol), palladium (II) acetate (6.4 mg, 0.028 mmol), tricyclohexylphosphine (16 mg, 0.057 mmol), and potassium carbonate (79 mg, 0.57 mmol) was added tetrahydrofuran (2.5 mL) and water (10 μL, 0.57 mmol). The mixture was degassed by sparging with argon (5 min) and heated to 65° C. for 6 h. The mixture was allowed to cool to rt, filtered, and concentrated in vacuo to afford tert-butyl ((1S,2R)-2-((5-cyano-6-(1H-indol-2-yl)pyrazin-2-yl)amino)cyclohexyl)carbamate. The residue was used without further purification in the subsequent transformation. MS ESI calcd. for C₂₄H₂₉N₆O₂ [M+H]⁺ 433, found 433.

Step 2: Tert-butyl ((1S,2R)-2-((5-cyano-6-(1H-indol-2-yl)pyrazin-2-yl)amino)cyclohexyl)carbamate (123 mg, 0.284 mmol) was dissolved in dichloromethane (2 mL). Trifluoroacetic acid (0.219 mL, 2.84 mmol) was added, and the solution was maintained 1 h at rt. The mixture was concentrated in vacuo, and the resultant residue was dissolved in MeOH, filtered, and submitted to purification via reverse phase HPLC (CH₃CN:H₂O with 0.1% acid modifier (TFA)) to afford 5-(((1R,2S)-2-aminocyclohexyl)amino)-3-(1H-indol-2-yl)pyrazine-2-carbonitrile as the corresponding trifluoroacetic acid salt, which was used directly in the subsequent transformation. MS ESI calcd. for C₁₉H₂₁N₆ [M+H]⁺ 333, found 333.

Step 3: 5-(((1R,2S)-2-Aminocyclohexyl)amino)-3-(1H-indol-2-yl)pyrazine-2-carbonitrile (241 mg, 0.725 mmol) was dissolved in DMSO (3.5 mL). Potassium hydroxide (203 mg, 3.63 mmol) and hydrogen peroxide (30% in water, 0.741 ml, 7.25 mmol) were added sequentially, and the resultant suspension was stirred vigorously for 1 h at rt. The mixture was filtered, and the resultant solution was submitted to purification via reverse phase HPLC (CH₃CN:H₂O with 0.1% acid modifier (TFA)) to afford a solid. The solid was suspended in 10% IPA:CHCl₃ (10 mL). Saturated aqueous sodium bicarbonate (10 mL) was added, and the layers were separated. The aqueous portion was then extracted with 10% IPA:CHCl₃ (2×10 mL). The combined organic extracts were dried over sodium sulfate, filtered, and concentrated in vacuo. The resultant solid was washed with acetonitrile and water (30 mL) and dried to afford 5-(((1R,2S)-2-aminocyclohexyl)amino)-3-(1H-indol-2-yl)pyrazine-2-carboxamide as a solid. MS ESI calcd. for C₁₉H₂₃N₆O [M+H]⁺ 351, found 351. ¹H NMR (500 MHz, DMSO-d₆) δ 12.51 (s, 1H), 8.05 (s, 1H), 7.92 (s, 1H), 7.60 (s, 1H), 7.57 (d, J=8.0 Hz, 1H), 7.48 (d, J=8.2 Hz, 1H), 7.26 (s, 1H), 7.20 (s, 1H), 7.13 (t, J=7.6 Hz, 1H), 6.99 (t, J=7.3 Hz, 1H), 4.21 (s, 1H), 3.06 (s, 1H), 1.73 (d, J=8.7, 1H), 1.66-1.45 (m, 5H), 1.38-1.341.36 (m, 2H).

The following compound was prepared in an analogous manner to that described in Example 2.1.

[M + H]⁺ [M + H]⁺ Ex. No. Structure Name Calc'd Obsv'd Form(s) 2.2

5-{[(2S)-2- aminopropyl]amino}-3-(1H- indol-2-yl)pyrazine-2- carboxamide 311.2 311 TFA Salt

Example 3 Example 3.1 5-(((3S,4S)-4-Amino-1,1-dioxidotetrahydro-2H-thiopyran-3-yl)amino)-3-(1H-indol-2-yl)pyrazine-2-carboxamide

Step 1: To a flask containing tert-butyl ((3S,4S)-3-((6-chloro-5-cyanopyrazin-2-yl)amino)-1,1-dioxidotetrahydro-2H-thiopyran-4-yl)carbamate (10.5 g, 26.1 mmol), 2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-indole (7.62 g, 31.4 mmol), and [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium (II), complex with dichloromethane (1.07 g, 1.31 mmol) was added dioxane (75 mL) and sodium carbonate (2 M aqueous, 26.1 mL, 52.3 mmol). The mixture was degassed by sparging with argon (5 min) and heated to 90° C. for 1.5 h. The mixture was allowed to cool to rt, then diluted with dichloromethane and water. The layers were separated, and the aqueous portion was extracted with dichloromethane. The combined organic extracts were dried over magnesium sulfate, filtered, and concentrated in vacuo to afford a residue, which was absorbed onto silica gil and purified by normal phase silica gel column chromatography (EtOAc:Hexanes). The material was then slurried in EtOAc, and hexanes was added while cooling the mixture to 0° C. The resultant solids were filtered and washed with hexanes to afford tert-butyl ((3S,4S)-3-((5-cyano-6-(1H-indol-2-yl)pyrazin-2-yl)amino)-1,1-dioxidotetrahydro-2H-thiopyran-4-yl)carbamate as a brown solid. MS ESI calcd. for C₂₃H₂₇N₆O₄S [M+H]⁺ 483, found 483.

Step 2: To a flask containing tert-butyl ((3S,4S)-3-((5-cyano-6-(1H-indol-2-yl)pyrazin-2-yl)amino)-1,1-dioxidotetrahydro-2H-thiopyran-4-yl)carbamate (10.0 g, 20.7 mmol) was added DMSO (60 mL). Sodium hydroxide (6 M aqueous, 10.4 mL, 62.2 mmol) was added to the mixture, followed by the slow addition of hydrogen peroxide (35% in water, 10.9 mL, 124 mmol). The resultant mixture was stirred vigorously for 20 minutes, then water (10 mL) was added. The resultant solid was filtered. The filtrate was diluted with EtOAc and heated to 60° C. with stirring for 1 h. The mixture was allowed to cool to rt, and hexanes (150 mL) was added. The solids were filtered and washed with hexanes to afford tert-butyl ((3S,4S)-3-((5-carbamoyl-6-(1H-indol-2-yl)pyrazin-2-yl)amino)-1,1-dioxidotetrahydro-2H-thiopyran-4-yl)carbamate as a solid. MS ESI calcd. for C₂₃H₂₉N₆O₅S [M+H]⁺ 501, found 501.

Step 3: To a flask containing tert-butyl ((3S,4S)-3-((5-carbamoyl-6-(1H-indol-2-yl)pyrazin-2-yl)amino)-1,1-dioxidotetrahydro-2H-thiopyran-4-yl)carbamate (5.00 g, 9.99 mmol) was added dioxane (8 mL). Methanesulfonic acid (1.95 mL, 30.0 mmol) was added, and the mixture was heated to 65° C. with stirring for 2 h. The mixture was allowed to cool to rt, and hexanes (5 mL) was added. The mixture was filtered, and the solid was washed with hexanes to afford a solid. The residue was dissolved in ammonia in methanol (7 M aqueous, 22.0 mL, 154 mmol) and heated to 50° C. for 30 min. The mixture was cooled to 0° C., filtered, washed with cold ethanol, and dried to afford 5-(((3S,4S)-4-amino-1,1-dioxidotetrahydro-2H-thiopyran-3-yl)amino)-3-(1H-indol-2-yl)pyrazine-2-carboxamide as a solid. MS ESI calcd. for C₁₈H₂₁N₆O₃S [M+H]⁺ 401, found 401. ¹H NMR (500 MHz, DMSO-d₆) δ 12.60 (s, 1H), 8.10 (s, 1H), 7.89 (s, 1H), 7.68 (s, 2H), 7.54 (d, J=7.8 Hz, 1H), 7.46 (d, J=8.2 Hz, 1H), 7.25 (s, 1H), 7.12 (t, J=7.5 Hz, 1H), 6.98 (t, J=7.4 Hz, 1H), 4.58 (s, 1H), 3.42-3.30 (m, 3H), 3.20 (d, J=13.4 Hz, 1H), 2.99 (d, J=11.4 Hz, 1H), 2.14 (t, J=13.6 Hz, 1H), 2.08-2.00 (m, 1H).

Example 4 Example 4.1 (S)-5-((2-aminopropyl)amino)-3-(5-bromo-1H-indol-2-yl)pyrazine-2-carboxamide

Step 1: To a flask containing (S)-tert-butyl 5-bromo-2-(6-((2-((tert-butoxycarbonyl)amino)propyl)amino)-3-cyanopyrazin-2-yl)-1H-indole-1-carboxylate (25 mg, 0.044 mmol) in dichloromethane (2 mL) was added trifluoroacetic acid (34 μL, 0.44 mmol), and the resultant mixture was heated to 40° C. for 1 h. The mixture was concentrated in vacuo to afford (S)-5-((2-aminopropyl)amino)-3-(5-bromo-1H-indol-2-yl)pyrazine-2-carbonitrile as the corresponding trifluoroacetic acid salt, and the resultant residue was used without further purification. MS ESI calcd. for C₁₆H₁₆BrN₆ [M+H]⁺ 371 and 373, found 371 and 373.

Step 2: To a flask containing (S)-5-((2-aminopropyl)amino)-3-(5-bromo-1H-indol-2-yl)pyrazine-2-carbonitrile (200 mg, 0.539 mmol) added DMSO (5 mL). Potassium hydroxide (151 mg, 2.69 mmol) and hydrogen peroxide (35% in water, 0.472 ml, 5.39 mmol) were added sequentially, and the resultant suspension was stirred vigorously for 1 h. The mixture was filtered and submitted to purification via reverse phase HPLC (CH₃CN:H₂O with 0.1% acid modifier (TFA)) to afford (S)-5-((2-aminopropyl)amino)-3-(5-bromo-1H-indol-2-yl)pyrazine-2-carboxamide as the corresponding trifluoroacetic acid salt as s solid. MS ESI calcd. for C₁₆H₁₈BrN₆O [M+H]⁺ 389 and 391, found 389 and 391. ¹H NMR (500 MHz, DMSO-d₆) δ 12.43 (s, 1H), 8.07 (s, 1H), 7.88-7.80 (m, 4H), 7.77 (s, 1H), 7.69 (s, 1H), 7.48 (d, J=8.7 Hz, 1H), 7.25 (dd, J=8.8, 1.3 Hz, 1H), 7.22 (s, 1H), 3.68-3.55 (m, 2H), 3.55-3.44 (m, 1H), 1.25 (d, J=6.5 Hz, 3H).

Example 5 Example 5.1 (S)-5-((2-Aminopropyl)amino)-3-(5-(1-methyl-1H-pyrazol-4-yl)-1H-indol-2-yl)pyrazine-2-carboxamide

Step 1: To a flask containing (S)-tert-butyl (1-((6-chloro-5-cyanopyrazin-2-yl)amino)propan-2-yl)carbamate (5.00 g, 16.0 mmol), (5-bromo-1-(tert-butoxycarbonyl)-1H-indol-2-yl)boronic acid (8.18 g, 24.1 mmol), and tetrakis(triphenylphosphine)palladium (0) (1.85 g, 1.60 mmol) was added dioxane (50 mL) and sodium carbonate (2 M aqueous, 16.0 mL, 32 mmol). The mixture was degassed by sparging with argon (5 min) and heated to 60° C. for 5 h. The mixture was allowed to cool to rt, then diluted with dichloromethane and water. The layers were separated, and the aqueous portion was extracted with dichloromethane. The combined organic extracts were dried over magnesium sulfate, filtered, and concentrated in vacuo to afford a residue, which was absorbed onto silica gel and purified by normal phase silica gel column chromatography (EtOAc:Hexanes). The material was then purified by SFC (methanol modifier) to afford (S)-tert-butyl 5-bromo-2-(6-((2-((tert-butoxycarbonyl)amino)propyl)amino)-3-cyanopyrazin-2-yl)-1H-indole-1-carboxylate. MS ESI calcd. for C₂₆H₃₂BrN₆O₄ [M+H]⁺ 571 and 573, found 571 and 573.

Step 2: To a flask containing (S)-tert-butyl 5-bromo-2-(6-((2-((tert-butoxycarbonyl)amino)propyl)amino)-3-cyanopyrazin-2-yl)-1H-indole-1-carboxylate (250 mg, 0.44 mmol) was added DMSO (1.5 mL). Sodium hydroxide (6 M aqueous, 292 μL, 1.75 mmol) was added to the mixture, followed by the slow addition of hydrogen peroxide (35% in water, 230 μL, 2.62 mmol). The resultant mixture was stirred vigorously for 20 minutes, then water was added. The resultant solid was filtered. The filtrate was diluted with dichloromethane and methanol and absorbed onto silica gel. Purification via normal phase silica gel column chromatography gave (S)-tert-butyl (1-((6-(5-bromo-1H-indol-2-yl)-5-carbamoylpyrazin-2-yl)amino)propan-2-yl)carbamate. MS ESI calcd. for C₂₁H₂₆BrN₆O₃ [M+H]⁺ 489 and 491, found 489 and 491.

Step 3: To a flask containing (S)-tert-butyl (1-((6-(5-bromo-1H-indol-2-yl)-5-carbamoylpyrazin-2-yl)amino)propan-2-yl)carbamate (40 mg, 0.082 mmol), 1-methyl-4-1H-pyrazoleboronic acid, pinacol ester (34 mg, 0.160 mmol), sodium carbonate (2 M aqueous, 82 μL, 0.16 mmol) and bis(diphenylphosphino)ferrocene]dichloropalladium (II), complex with dichloromethane (6.0 mg, 8.2 μmol) was added dioxane (1 mL). The mixture was degassed by sparging with argon (5 min), then heated to 90° C. for 16 h. The mixture was allowed to cool to rt, filtered, and concentrated in vacuo to afford (S)-tert-butyl (1-((5-carbamoyl-6-(5-(1-methyl-1H-pyrazol-4-yl)-1H-indol-2-yl)pyrazin-2-yl)amino)propan-2-yl)carbamate. The resultant residue was used without further purification in the subsequent transformation. MS ESI calcd. for C₂₅H₃₁N₈O₃ [M+H]⁺ 491, found 491.

Step 4: (S)-Tert-butyl (1-((5-carbamoyl-6-(5-(1-methyl-1H-pyrazol-4-yl)-1H-indol-2-yl)pyrazin-2-yl)amino)propan-2-yl)carbamate (40 mg, 0.082 mmol) was dissolved in dichloromethane (1 mL). Trifluoroacetic acid (63 μL, 0.82 mmol) was added, and the solution was maintained 1 h at rt. The mixture was concentrated in vacuo, and the resultant residue was dissolved in DMSO and submitted to purification via reverse phase HPLC (CH₃CN:H₂O with 0.1% acid modifier (TFA)) to provide (S)-5-((2-aminopropyl)amino)-3-(5-(1-methyl-1H-pyrazol-4-yl)-1H-indol-2-yl)pyrazine-2-carboxamide as the corresponding trifluoroacetic acid salt as a solid. MS ESI calcd. for C₂₀H₂₃N₈O [M+H]⁺ 391, found 391. ¹H NMR (500 MHz, CD₃OD) δ 7.88 (s, 1H), 7.83 (s, 1H), 7.79 (s, 1H), 7.74 (s, 1H), 7.45 (d, J=8.5 Hz, 1H), 7.39 (dd, J=8.5, 1.6 Hz, 1H), 7.34 (s, 1H), 3.93 (s, 3H), 3.83 (dd, J=17.2, 7.9 Hz, 1H), 3.75-3.68 (m, 2H), 1.42 (d, J=7.0 Hz, 3H).

Example 6 Example 6.1 (S)-5-((2-Aminopropyl)amino)-3-(5-(2-(2-oxopyrrolidin-1-yl)ethyl)-1H-indol-2-yl)pyrazine-2-carboxamide

To a vial was added tert-butyl 5-bromo-2-(6-((2-((tert-butoxycarbonyl)amino)propyl)amino)-3-cyanopyrazin-2-yl)-1H-indole-1-carboxylate (114 mg, 0.199 mmol), potassium trifluoro(2-(2-oxopyrrolidin-1-yl)ethyl)borate (88 mg, 0.40 mmol), chloro[(di(1-adamantyl)-N-butylphosphine)-2-(2-aminobiphenyl)]palladium(II) (134 mg, 0.200 mmol), cyclopentyl methyl ether (1.5 mL) and aqueous cesium carbonate (2.0 M, 0.60 mL, 1.2 mmol). The reaction was heated to 110° C. for 18 hours. Upon cooling to room temperature, TFA (1 mL) was added and the mixture was concentrated under reduced pressure. The residue was then taken up in DMSO (1 mL). Potassium hydroxide (112 mg, 2.00 mmol) and hydrogen peroxide (35% in H₂O, 0.26 mL, 3.0 mmol) were added and the mixture was stirred for 10 minutes. MeOH and AcOH were added and the mixture was filtered, concentrated under reduced pressure and purified via reverse phase HPLC to afford (S)-5-((2-aminopropyl)amino)-3-(5-(2-(2-oxopyrrolidin-1-yl)ethyl)-1H-indol-2-yl)pyrazine-2-carboxamide as the TFA salt. MS ESI calcd. for C₂₂H₂₈N₂O₂ [M+H]⁺ 422, found 422. ¹H NMR (600 MHz, DMSO): δ 12.14 (s, 1 H), 8.02 (s, 1 H), 7.87 (br s, 3H), 7.81 (s, 1H), 7.76 (t, J=6.0 Hz, 1 H); 7.63 (s, 1H), 7.39 (d, J=9.0 Hz, 1 H); 7.37 (s, 1 H); 7.18 (s, 1 H); 7.00 (dd, J=8.5 Hz, J=1.5 Hz, 1 H); 3.62-3.59 (m, 2 H); 3.51-3.49 (m, 1 H); 3.44-3.36 (m, 2 H); 3.25 (t, J=7.0 Hz, 2 H); 2.77 (t, J=7.4 Hz, 2 H); 2.13 (t, J=8.0 Hz, 2 H); 1.85-1.80 (m, 2 H); 1.24 (d, J=6.6 Hz, 3 H).

Example 7 Example 7.1 5-{[(1R,2S)-2-aminocyclohexyl]amino}-3-(5-chloro-1H-indol-2-yl)pyrazine-2-carboxamide

Step 1: A mixture of tert-butyl ((1S,2R)-2-((6-chloro-5-cyanopyrazin-2-yl)amino)cyclohexyl)carbamate (80 mg, 0.23 mmol), (1-(tert-butoxycarbonyl)-5-chloro-1H-indol-2-yl)boronic acid (134 mg, 0.455 mmol), and 1,1′-bis(diphenylphosphino)ferrocenedichloro palladium(II) dichloromethane complex (17 mg, 0.023 mmol) was diluted with sodium carbonate (2.0 M in water, 0.227 ml, 0.455 mmol) and dioxane (2.0 mL). The mixture was purged with argon via subsurface bubbling for 5 minutes, and the mixture was then heated to 90° C. for 2.5 hours, after which time the mixture was allowed to cool to ambient temperature. The mixture was filtered through CELITE and the filtrate was concentrated under reduced pressure to afford tert-butyl 2-[6-({(1R,2S)-2-[(tert-butoxycarbonyl)amino]cyclohexyl}amino)-3-cyanopyrazin-2-yl]-5-chloro-1H-indole-1-carboxylate. The isolated material was used without further purification in the subsequent reaction. MS ESI calcd. for C₂₉H₃₆ClN₆O₄ [M+H]⁺ 567, found 567.

Step 2: A mixture of tert-butyl 2-[6-({(1R,2S)-2-[(tert-butoxycarbonyl)amino]cyclohexyl}amino)-3-cyanopyrazin-2-yl]-5-chloro-1H-indole-1-carboxylate (0.129 g, 0.227 mmol) in dichloromethane (1.0 mL) was diluted with TFA (0.175 ml, 2.270 mmol) and stirred at ambient temperature for 1 hour. The mixture was concentrated under reduced pressure to afford 5-{[(1R,2S)-2-aminocyclohexyl]amino}-3-(5-chloro-1H-indol-2-yl)pyrazine-2-carbonitrile. The isolated material was used without further purification in the subsequent reaction. MS ESI calcd. for C₁₉H₂₀ClN₆ [M+H]⁺ 367, found 367.

Step 3: Potassium hydroxide (64 mg, 1.1 mmol) and hydrogen peroxide (30% solution in water, 0.232 ml, 2.270 mmol) were added sequentially to a mixture of 5-{[(1R,2S)-2-aminocyclohexyl]amino}-3-(5-chloro-1H-indol-2-yl)pyrazine-2-carbonitrile in DMSO (1.5 mL). The mixture was stirred for 1 hour at ambient temperature. The crude reaction mixture was purified directly by reverse phase HPLC (C-18; eluting with acetonitrile/water with 0.1% TFA modifier) to afford 5-{[(1R,2S)-2-aminocyclohexyl]amino}-3-(5-chloro-1H-indol-2-yl)pyrazine-2-carboxamide as a TFA salt. MS ESI calcd. for C₁₉H₂₂ClN₆O [M+H]⁺ 385, found 385. ¹H NMR (600 MHz, DMSO-d₆) δ 12.31 (s, 1H), 8.02 (s, 1H), 7.95 (s, 1H), 7.76-7.66 (br s, 3H), 7.63 (s, 1H), 7.61 (s, 1H), 7.52-7.46 (m, 2H), 7.17 (s, 1H), 7.12 (dd, J=8.4, 1.8 Hz, 1H), 4.62 (s, 1H), 1.82-1.60 (m, 7H), 1.50-1.37 (m, 2H).

The following compounds were prepared in an analogous manner of that described in Example 7.1.

Ex. [M + H]+ [M + H]+ No. Structure Name Calc'd Obsv'd Form(s) 7.2

5-{[(2S)-2- aminopropyl]amino}-3-(4- bromo-1H-indol-2- yl)pyrazine-2- carboxamide 389.1 389 TFA Salt 7.3

5-[(3-aminotetrahydro-2H- pyran-4-yl)amino]-3-(4- chloro-1H-indol-2- yl)pyrazine-2- carboxamide 387.1 387 Free Base 7.4

5-[(3-aminotetrahydro-2H- pyran-4-yl)amino]-3-(4- chloro-1H-indol-2- yl)pyrazine-2- carboxamide 387.1 387 Free Base 7.5

5-{[(3R,4R)-3- aminotetrahydro-2H- pyran-4-yl]amino}-3-(5- methoxy-1H-indol-2- yl)pyrazine-2- carboxamide 383.2 383 TFA Salt 7.6

5-{[(3R,4R)-3- aminotetrahydro-2H- pyran-4-yl]amino}-3-(6- fluoro-1H-indol-2- yl)pyrazine-2- carboxamide 371.2 371 TFA Salt 7.7

5-{[(3S,4S)-4-amino-1,1- dioxidotetrahydro-2H- thiopyran-3-yl]amino}-3- (4-chloro-1H-indol-2- yl)pyrazine-2- carboxamide 435.1 435 TFA Salt 7.8

5-{[(3S,4S)-4-amino-1,1- dioxidotetrahydro-2H- thiopyran-3-yl]amino}-3- (5-methoxy-1H-indol-2- yl)pyrazine-2- carboxamide 431.2 431 TFA Salt 7.9

5-{[(3S,4S)-4-amino-1,1- dioxidotetrahydro-2H- thiopyran-3-yl]amino}-3- (5-fluoro-1H-indol-2- yl)pyrazine-2- carboxamide 419.1 419 TFA Salt 7.10

5-{[(3S,4S)-4-amino-1,1- dioxidotetrahydro-2H- thiopyran-3-yl]amino}-3- (5-chloro-1H-indol-2- yl)pyrazine-2- carboxamide 435.1 435 TFA Salt

Example 8 Example 8.1 (R)-5-((2-Amino-3-methoxypropyl)amino)-3-(1H-indol-2-yl)pyrazine-2-carboxamide

Step 1: To a flask containing (R)-tert-butyl (1-((6-chloro-5-cyanopyrazin-2-yl)amino)-3-methoxypropan-2-yl)carbamate (100 mg, 0.30 mmol), 2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-indole (144 mg, 0.591 mmol) and 1,1′-bis(diphenylphosphino)ferrocenedichloro palladium (II) dichloromethane complex (22 mg, 0.030 mmol) was added dioxane (3.0 mL) and sodium carbonate (2.0 M in H₂O, 300 μl, 0.59 mmol). The mixture was evacuated/purged five times with argon and then heated to 90° C. for 2.5 hours. The mixture was allowed to cool to room temperature, diluted with ethyl acetate and water and the organic layer was separated, dried over magnesium sulfate, filtered and concentrated under reduced pressure. The residue was purified by column chromatography on silica gel to afford (R)-tert-butyl (1-((5-cyano-6-(1H-indol-2-yl)pyrazin-2-yl)amino)-3-methoxypropan-2-yl)carbamate. MS ESI calcd. for C₁₈H₁₉N₆O₃ [M-C₄H₉+H]⁺ 367, found 367.

Step 2: To a mixture of (R)-tert-butyl (1-((5-cyano-6-(1H-indol-2-yl)pyrazin-2-yl)amino)-3-methoxypropan-2-yl)carbamate (83 mg, 0.20 mmol) in dichloromethane (1.2 mL) was added TFA (150 μl, 2.0 mmol) and the mixture was stirred at room temperature for one hour. The mixture was diluted with methanol and then concentrated under reduced pressure. The residue was taken up in methanol again and then concentrated under reduced pressure. The residue was then placed under vacuum. The product was taken on to the next step without further purification. MS ESI calcd. for C₁₇H₁₉N₆O [M+H]⁺ 323, found 323.

Step 3: To a mixture of (R)-5-((2-amino-3-methoxypropyl)amino)-3-(1H-indol-2-yl)pyrazine-2-carbonitrile (63 mg, 0.20 mmol) in DMSO (1.0 mL) was added potassium hydroxide (55 mg, 0.98 mmol) and then hydrogen peroxide (30% w/w in water, 200 μl, 1.95 mmol) and the reaction was stirred at room temperature for one hour. The mixture was then filtered and purified by HPLC to afford (R)-5-((2-amino-3-methoxypropyl)amino)-3-(1H-indol-2-yl)pyrazine-2-carboxamide as the TFA salt. MS ESI calcd. for C₁₇H₂₁N₆O₂ [M+H]⁺ 341, found 341. ¹H NMR (500 MHz, DMSO-d₆) δ 12.26 (s, 1H), 8.08 (s, 1H), 8.04 (s, 2H), 7.85 (s, 1H), 7.79 (t, J=5.8 Hz, 1H), 7.70 (s, 1H), 7.58 (d, J=8.0 Hz, 1H), 7.50 (d, J=8.2 Hz, 1H), 7.32-7.28 (m, 1H), 7.16 (dd, J=11.2, 4.0 Hz, 1H), 7.03 (t, J=7.5 Hz, 1H), 3.73-3.67 (m, 1H), 3.64-3.59 (m, 2H), 3.59-3.52 (m, 2H), 3.35 (s, 3H).

The following compounds were prepared in an analogous manner of that described in Example 8.1.

Ex. [M + H]+ [M + H]+ No. Structure Name Calc'd Obsv'd Form 8.2

5-{[(3R,4R)-4-amino-1,1- dioxidotetrahydro-2H- thiopyran-3-yl]amino}-3- (1H-indol-2-yl)pyrazine-2- carboxamide 401.1 401 TFA Salt 8.3

5-{[(1R,2S)-2- aminocyclohexyl]amino}- 3-(4-methyl-1H-indol-2- yl)pyrazine-2- carboxamide 365.2 365 TFA Salt 8.4

5-{[(3R,4R)-3- aminotetrahydro-2H- pyran-4-yl]amino}-3-(4- methyl-1H-indol-2- yl)pyrazine-2- carboxamide 367.2 367 TFA Salt 8.5

5-{[(3R,4R)-3- aminotetrahydro-2H- pyran-4-yl]amino}-3-(4- methoxy-1H-indol-2- yl)pyrazine-2- carboxamide 383.2 383 TFA Salt 8.6

5-{[(3R,4R)-3- aminotetrahydro-2H- pyran-4-yl]amino}-3-(1H- indol-2-yl)pyrazine-2- carboxamide 353.2 353 TFA Salt 8.7

5-{[(2R)-2-amino-3- methoxypropyl]amino}-3- (4-methoxy-1H-indol-2- yl)pyrazine-2- carboxamide 371.2 371 TFA Salt

Example 9 Example 9.1 5-[(2-Aminoethyl)amino]-3-(5-fluoro-1H-indol-2-yl)pyrazine-2-carboxamide

Step 1: Potassium carbonate (3.95 g, 28.5 mmol) was added to a mixture of tert-butyl {2-[(6-chloro-5-cyanopyrazin-2-yl)amino]ethyl}carbamate (10.0 g, 33.6 mmol) in DMSO (100 mL) at ambient temperature. Hydrogen peroxide (35% solution in water, 5.18 mL, 59.1 mmol) was then added to the reaction mixture (an ice bath was used to keep reaction temperature below 25° C. due to exotherm). After 1 hour, the mixture was further diluted with potassium hydroxide (1.0 M in water, 5.0 mL, 5.0 mmol) followed by hydrogen peroxide (35% solution in water, 5.0 mL, 57 mmol). The reaction mixture was stirred for 18 hours at ambient temperature, and then diluted with water. The resulting suspension was filtered and the collected solids were washed with additional water and then dried to afford tert-butyl {2-[(5-carbamoyl-6-chloropyrazin-2-yl)amino]ethyl}carbamate. The material was used in the subsequent reaction without further purification. ¹H NMR (600 MHz, DMSO-d₆) δ 7.95 (s, 1H), 7.79 (s, 1H), 7.64 (s, 1H), 7.26 (s, 1H), 6.87 (t, J=5.4 Hz, 1H), 3.30-3.26 (m, 2H), 3.09-3.05 (m, 2H), 1.32 (s, 9H).

Step 2: Tert-butyl {2-[(5-carbamoyl-6-chloropyrazin-2-yl)amino]ethyl}carbamate (150 mg, 0.475 mmol), (1-(tert-butoxycarbonyl)-5-fluoro-1H-indol-2-yl)boronic acid (212 mg, 0.760 mmol), and 1,1′-bis(diphenylphosphino)ferrocenedichloro palladium (II) dichloromethane complex (35 mg, 0.048 mmol) were added to a vial and degassed with argon for 5 minutes. The mixture was diluted with sodium carbonate (2.0 M in water, 0.475 ml, 0.950 mmol) and dioxane (3.0 mL) and then degassed with argon via subsurface bubbling for 5 minutes. The mixture was then heated to 90° C. for 2.5 hours. The mixture was allowed to cool to ambient temperature and filtered. The filtrate was concentrated under reduced pressure to afford tert-butyl 2-[6-({2-[(tert-butoxycarbonyl)amino]ethyl}amino)-3-carbamoylpyrazin-2-yl]-5-fluoro-1H-indole-1-carboxylate. The material was used in the subsequent reaction without further purification. MS ESI calcd. for C₂₅H₃₂FN₆O₅ [M+H]⁺ 515, found 515.

Step 3: tert-Butyl 2-[6-({2-[(tert-butoxycarbonyl)amino]ethyl}amino)-3-carbamoylpyrazin-2-yl]-5-fluoro-1H-indole-1-carboxylate (117 mg, 0.227 mmol) was dissolved in dichloromethane (2.0 mL). Hydrochloric acid (4.0 M in dioxane, 2.0 mL, 8.0 mmol) was added to the mixture and the mixture was stirred at ambient temperature for 1 hour. The mixture was concentrated under reduced pressure to afford the crude product residue. The crude product residue was purified by reverse phase HPLC (C-18; eluting with acetonitrile/water+0.1% TFA modifier) to afford 5-((2-aminoethyl)amino)-3-(5-fluoro-1H-indol-2-yl)pyrazine-2-carboxamide as a TFA salt. MS ESI calcd. for C₁₅H₁₆FN₆O [M+H]⁺ 315, found 315. ¹H NMR (600 MHz, DMSO-d₆) δ 12.37 (s, 1H), 8.04 (s, 1H), 7.82 (s, 1H), 7.80-7.74 (br s, 3H), 7.71 (t, J=6.0 Hz, 1H), 7.65 (s, 1H), 7.48 (dd, J=9.0 Hz, 4.8 Hz, 1H), 7.30 (dd, J=9.6, 2.4 Hz, 1H), 7.22 (s, 1H), 6.98 (td, J=9.0, 2.4 Hz, 1H), 3.70-3.64 (m, 2H), 3.10-3.03 (m, 2H).

Example 10 Example 10.1 5-(((3R,4R)-3-aminotetrahydro-2H-pyran-4-yl)amino)-3-(4-methoxy-1H-pyrrolo[2,3-c]pyridin-2-yl)pyrazine-2-carboxamide

Step 1: To a mixture of tert-butyl 4-methoxy-1H-pyrrolo[2,3-c]pyridine-1-carboxylate (316 mg, 1.27 mmol) in THF (2.0 mL) at −78° C. was added n-butyllithium (1.6 M in hexanes, 870 μl, 1.4 mmol) dropwise followed by triisopropyl borate (325 μl, 1.40 mmol) dropwise. The mixture was stirred at −78° C. for one hour and then allowed to warm to room temperature for one hour. To the mixture was added potassium phosphate, tribasic (1.4 mL, 1.4 mmol) followed by tert-butyl ((3R,4R)-4-((6-chloro-5-cyanopyrazin-2-yl)amino)tetrahydro-2H-pyran-3-yl)carbamate (150 mg, 0.42 mmol) and chloro(2-dicyclohexylphosphino-2′,4′,6′-tri-i-propyl-1,1′-biphenyl)(2′-amino-1,1′-biphenyl-2-yl) palladium(II) (40 mg, 0.051 mmol). The headspace above the mixture was evacuated via vacuum and then purged five times with argon. The reaction mixture was stirred at 60° C. for 2 h. The reaction mixture was then allowed to cool to room temperature and quenched with water and ethyl acetate. The organic layer was separated, dried over magnesium sulfate, filtered and concentrated under reduced pressure. The residue was purified by column chromatography to afford tert-butyl 2-(6-(((3R,4R)-3-((tert-butoxycarbonyl)amino)tetrahydro-2H-pyran-4-yl)amino)-3-cyanopyrazin-2-yl)-4-methoxy-1H-pyrrolo[2,3-c]pyridine-1-carboxylate. MS ESI calcd. for C₂₈H₃₆N₇O₆ [M+H]⁺ 566, found 566.

Step 2: To a mixture of tert-butyl 2-(6-(((3R,4R)-3-((tert-butoxycarbonyl)amino)tetrahydro-2H-pyran-4-yl)amino)-3-cyanopyrazin-2-yl)-4-methoxy-1H-pyrrolo[2,3-c]pyridine-1-carboxylate (139 mg, 0.246 mmol) in DCM (2.0 mL) was added TFA (190 μl, 2.5 mmol) and the mixture was heated to 50° C. for one hour. The mixture was allowed to cool to room temperature and then diluted with methanol and concentrated under reduced pressure. The residue was then diluted with methanol and concentrated again to afford 5-(((3R,4R)-3-aminotetrahydro-2H-pyran-4-yl)amino)-3-(4-methoxy-1H-pyrrolo[2,3-c]pyridin-2-yl)pyrazine-2-carbonitrile as the TFA salt. The crude product was taken on without further purification. MS ESI calcd. for C₁₈H₂₀N₇O₂ [M+H]⁺ 366, found 366.

Step 3: To a mixture of 5-(((3R,4R)-3-aminotetrahydro-2H-pyran-4-yl)amino)-3-(4-methoxy-1H-pyrrolo[2,3-c]pyridin-2-yl)pyrazine-2-carbonitrile (90 mg, 0.25 mmol) in DMSO (1.0 mL) was added potassium hydroxide (69 mg, 1.23 mmol) followed by hydrogen peroxide (30% in water, 250 μl, 2.46 mmol) and the mixture was stirred for one hour. The mixture was then filtered and purified by reverse phase HPLC to afford 5-(((3R,4R)-3-aminotetrahydro-2H-pyran-4-yl)amino)-3-(4-methoxy-1H-pyrrolo[2,3-c]pyridin-2-yl)pyrazine-2-carboxamide as the TFA salt. MS ESI calcd. for C₁₈H₂₂N₇O₃ [M+H]⁺ 384, found 384. ¹H NMR (500 MHz, DMSO-d₆) δ 9.03 (s, 1H), 8.23 (s, 1H), 8.06 (s, 1H), 8.04-7.99 (m, 4H), 7.85 (s, 1H), 7.45 (s, 1H), 4.55-4.45 (m, 1H), 4.09 (s, 3H), 4.03-3.97 (m, 1H), 3.97-3.91 (m, 1H), 3.83-3.76 (m, 2H), 3.66-3.57 (m, 1H), 2.13-1.96 (m, 1H), 1.83-1.74 (m, 1H).

The following compounds were prepared in an analogous manner of that described in Example 10.1.

Ex. [M + H]+ [M + H]+ No. Structure Name Calc'd Obsv'd Form 10.2

5-(((3S,4S)-4-amino-1,1- dioxidotetrahydro-2H- thiopyran-3-yl)amino)-3-(5- (trifluoromethyl)-1H-indol-2- yl)pyrazine-2-carboxamide 469 469 TFA Salt 10.3

5-{[(3R,4R)-3- aminotetrahydro-2H-pyran-4- yl]amino}-3-(2,3-dihydro-7H- [1,4]dioxin[2,3-e]indol-8- yl)pyrazine-2-carboxamide 411.2 411 TFA Salt 10.4

5-{[(3R,4R)-3- aminotetrahydro-2H-pyran-4- yl]amino}-3-(4,5-dimethoxy- 1H-indol-2-yl)pyrazine-2- carboxamide 413.2 413 TFA Salt 10.5

5-{[(3R,4R)-3- aminotetrahydro-2H-pyran-4- yl]amino}-3-(5-ethyl-1H- indol-2-yl)pyrazine-2- carboxamide 381.2 381 TFA Salt 10.6

5-{[(3R,4R)-3- aminotetrahydro-2H-pyran-4- yl]amino}-3-(4-ethyl-1H- indol-2-yl)pyrazine-2- carboxamide 381.2 381 TFA Salt 10.7

5-{[(3R,4R)-3- aminotetrahydro-2H-pyran-4- yl]amino}-3-(1H-pyrrolo[3,2- c]pyridin-2-yl)pyrazine-2- carboxamide 354.2 354 TFA Salt 10.8

5-{[(3R,4R)-3- aminotetrahydro-2H-pyran-4- yl]amino}-3-(1H-pyrrolo[3,2- b]pyridin-2-yl)pyrazine-2- carboxamide 354.2 354 TFA Salt 10.9

5-{[(3R,4R)-3- aminotetrahydro-2H-pyran-4- yl]amino}-3-(1H-pyrrolo[2,3- c]pyridin-2-yl)pyrazine-2- carboxamide 354.2 354 TFA Salt

Example 11 Example 11.1 (S)-5-((2-Aminopropyl)amino)-3-(phenylethynyl)pyrazine-2-carboxamide

Step 1: To a mixture of (S)-tert-butyl (1-((6-chloro-5-cyanopyrazin-2-yl)amino)propan-2-yl)carbamate (4.00 g, 12.8 mmol), Pd(PPh₃)₄ (1.04 g, 0.898 mmol), and CuI (0.24 g, 1.3 mmol) in acetonitrile (30 mL) was added Et₃N (2.68 mL, 19.3 mmol) followed by phenylacetylene (1.69 mL, 15.4 mmol). The reaction mixture was heated to 60° C. for 3 h. Upon cooling to room temperature, the mixture was absorbed on silica gel and then concentrated under reduced pressure. The mixture was purified by flash chromatography (0 to 100% EtOAc/hexanes) to afford (S)-tert-butyl (1-((5-cyano-6-(phenylethynyl)pyrazin-2-yl)amino)propan-2-yl)carbamate as an oil. MS ESI calcd. for C₂₁H₂₃N₅NaO₂ [M+Na]⁺ 400, found 400.

Step 2: To a mixture of (S)-tert-butyl (1-((5-cyano-6-(phenylethynyl)pyrazin-2-yl)amino)propan-2-yl)carbamate (300 mg, 0.80 mmol) in DMSO (1 mL) was added NaOH (6.0 M in H₂O, 397 μL, 2.4 mmol) followed by the dropwise addition of H₂O₂ (30% in H₂O, 418 μL, 4.8 mmol) over five minutes. Upon completion, the mixture was stirred for 20 min and then water (4 mL) was added. The resulting slurry was filtered and the collected solid was washed with water (2×2 mL) and then dried under a nitrogen bag to afford (S)-tert-butyl (1-((5-carbamoyl-6-(phenylethynyl)pyrazin-2-yl)amino)propan-2-yl)carbamate as a solid. MS ESI calcd. for C₂₁H₂₆N₅O₃ [M+H]⁺ 396, found 396.

Step 3: To a mixture of (S)-tert-butyl (1-((5-carbamoyl-6-(phenylethynyl)pyrazin-2-yl)amino)propan-2-yl)carbamate (200 mg. 0.51 mmol) in dioxane (2 mL) was added HCl (4 N in dioxane, 0.44 mL, 1.77 mmol). The resulting mixture was heated to 40° C. for 90 minutes and then allowed to cool to room temperature. Hexanes (4 mL) were added and the resulting slurry was filtered and the solids were washed with hexanes (4 mL). After drying under a nitrogen bag for 4 h, the solids were purified by reverse phase HPLC (CH₃CN:H₂O with 0.1% TFA modifier) to afford (S)-5-((2-aminopropyl)amino)-3-(phenylethynyl)pyrazine-2-carboxamide as the corresponding trifluoroacetic acid salt as a solid. MS ESI calcd. for C₁₆H₁₈N₅O [M+H]⁺ 296, found 296. ¹H NMR (600 MHz, CD₃OD) δ 7.91 (s, 1H), 7.64-7.60 (m, 2H), 7.42-7.35 (m, 3H), 3.66-3.56 (m, 3H), 1.34 (d, J=6.6 Hz, 3H).

Example 12 Examples 12.1 and 12.2 5-(((3S,4S)-4-Amino-1,1-dioxidotetrahydro-2H-thiopyran-3-yl)amino)-3-(3-chloro-1H-indol-2-yl)pyrazine-2-carboxamide and (2-(6-(((3S,4S)-4-amino-1,1-dioxidotetrahydro-2H-thiopyran-3-yl)amino)-3-carbamoylpyrazin-2-yl)-1H-indol-3-yl)dimethylsulfonium

To a mixture of tert-butyl ((3S,4S)-3-((5-carbamoyl-6-(1H-indol-2-yl)pyrazin-2-yl)amino)-1,1-dioxidotetrahydro-2H-thiopyran-4-yl)carbamate (8.94 g, 17.8 mmol) in DMSO (1.8 mL) and dioxane (100 mL) was HCl (4.0 M in dioxane, 17.8 mL, 71 mmol) and the mixture was heated to 55° C. for 4 h. Upon cooling to room temperature, hexanes (100 mL) were added and the slurry was filtered. The collected solids were dried for 14 h under a nitrogen bag. The solids were then purified by reverse phase HPLC (CH₃CN:H₂O with 0.1% TFA modifier) to afford 5-(((3S,4S)-4-amino-1,1-dioxidotetrahydro-2H-thiopyran-3-yl)amino)-3-(3-chloro-1H-indol-2-yl)pyrazine-2-carboxamide and (2-(6-(((3S,4S)-4-amino-1,1-dioxidotetrahydro-2H-thiopyran-3-yl)amino)-3-carbamoylpyrazin-2-yl)-1H-indol-3-yl)dimethylsulfonium as their corresponding trifluoroacetic acid salts.

Peak 1—solid; (2-(6-(((3S,4S)-4-amino-1,1-dioxidotetrahydro-2H-thiopyran-3-yl)amino)-3-carbamoylpyrazin-2-yl)-1H-indol-3-yl)dimethylsulfonium (Example 12.2). MS ESI calcd. for C₂₀H₂₅N₆O₃S₂ [M]′ 461, found 461. ¹H NMR (600 MHz, DMSO-d₆) δ 12.85 (s, 1H), 8.51-8.48 (m, 2H), 8.45-8.40 (m, 1H), 8.20 (d, J=8.6 Hz, 1H), 8.18 (s, 1H), 8.16 (d, J=2.0 Hz, 1H), 7.67 (d, J=8.5 Hz, 1H), 7.66 (d, J=2.0 Hz, 1H), 7.39 (t, J=7.7 Hz, 1H), 7.30 (t, J=7.7 Hz, 1H), 4.82-4.74 (m, 1H); 3.99-3.90 (m, 1H), 3.58 (dd, J=14.3 Hz, 8.7 Hz, 1H), 3.52-3.50 (m, 1H), 3.35-3.31 (m, 2H), 3.30 (s, 6H), 2.50-2.42 (m, 1H); 2.24-2.16 (m, 1H).

Peak 2—solid; 5-(((3S,4S)-4-amino-1,1-dioxidotetrahydro-2H-thiopyran-3-yl)amino)-3-(3-chloro-1H-indol-2-yl)pyrazine-2-carboxamide (Example 12.1). MS ESI calcd. for C₁₈H₂₀ClN₆O₃S [M+H]⁺ 435, found 435. ¹H NMR (600 Mhz, DMSO-d₆) δ 11.83 (s, 1H), 8.17-8.11 (m, 2H), 8.04 (s, 1H), 7.91-7.85 (m, 1H), 7.83 (d, J=2.0 Hz, 1H), 7.47 (d, J=8.2 Hz, 1H), 7.45 (d, J=8.2 Hz, 1H), 7.37 (d, J=2.0 Hz, 1H), 7.21 (td, J=7.7 Hz, 1.2 Hz, 1H), 7.11 (td, J=7.6 Hz, 0.7 Hz, 1H), 4.83-4.74 (m, 1H), 3.95-3.82 (m, 1H), 3.56-3.53 (m, 2H), 3.33-3.28 (m, 2H), 2.45-2.38 (m, 1H), 2.23-2.17 (m, 1H).

Example 13 Example 13.1 (S)-5-((2-Aminopropyl)amino)-3-(5-(pyridin-3-yl)-1H-indol-2-yl)pyrazine-2-carboxamide

To a flask containing (S)-5-(2-aminopropyl)amino)-3-(5-bromo-1H-indol-2-yl)pyrazine-2-carboxamide (40 mg, 0.10 mmol), 3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine (42 mg, 0.21 mmol), sodium carbonate (2 M aqueous, 103 μl, 0.206 mmol) and [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium (II), complex with dichloromethane (7.5 mg, 10 μmol) was added dioxane (1 mL). The mixture was degassed by sparging with argon (5 min), then heated to 90° C. for 16 h. The mixture was allowed to cool to rt, filtered, and concentrated in vacuo. The residues, dissolved in DMSO, were filtered and submitted to purification via reverse phase HPLC (CH₃CN:H₂O with 0.1% acid modifier (TFA)) to afford (S)-5-((2-aminopropyl)amino)-3-(5-(pyridin-3-yl)-1H-indol-2-yl)pyrazine-2-carboxamide as the corresponding trifluoroacetic acid salt as a solid. MS ESI calcd. for C₂₁H₂₂N₇O [M+H]⁺ 388, found 388. ¹H NMR (500 MHz, CD₃OD) δ 9.11 (d, J=2.2 Hz, 1H), 8.82-8.77 (m, 1H), 8.69 (dd, J=10.1, 5.6 Hz, 1H), 8.06 (d, J=1.2 Hz, 1H), 8.02 (dd, J=8.1, 5.6 Hz, 1H), 7.90 (s, 1H), 7.70-7.65 (m, 1H), 7.63-7.58 (m, 1H), 7.47 (d, J=1.2 Hz, 1H), 3.91-3.82 (dd, J=17.2, 7.9 Hz, 1H), 3.76-3.68 (m, 2H), 1.43 (d, J=6.3 Hz, 3H).

Example 14 Example 14.1 5-(2-Aminoethylamino)-3-(1H-indol-2-yl)pyrazine-2-carboxamide

Step 1: To a mixture of tert-butyl (2-((6-chloro-5-cyanopyrazin-2-yl)amino)ethyl)carbamate (54 mg, 0.18 mmol), (1-(tert-butoxycarbonyl)-1H-indol-2-yl)boronic acid (95 mg, 0.36 mmol), Pd₂(dba)₃ (8 mg, 9 μmol), Xphos (8.7 mg, 0.020 mmol) and K₃PO₄.3H₂O (145 mg, 0.540 mmol) was added dioxane (2 mL) and H₂O (0.5 mL). The mixture was heated to 90° C. for 3 hours. Upon cooling to room temperature, H₂O (50 mL) was added and the mixture was extracted with ethyl acetate (3×50 mL). The combined organics were dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by prep-TLC (1:1 petroleum ether/EtOAc) to afford tert-butyl (2-((5-cyano-6-(1H-indol-2-yl)pyrazin-2-yl)amino)ethyl)carbamate as a solid. MS ESI calc'd. for C₂₀H₂₃N₆O₂[M+H]⁺ 379, found 379. ¹H NMR (400 MHz, CD₃OD) δ 8.21 (d, J=8.0 Hz, 1H), 7.94 (s, 1H), 7.68 (d, J=8.0 Hz, 1H), 7.45-7.41 (m, 1H), 7.33-7.29 (m, 1H), 7.02 (s, 1H), 3.56-3.53 (m, 2H), 3.29-3.26 (m, 2H), 1.45 (s, 9H).

Step 2: To a mixture of tert-butyl 2-(5-cyano-6-(1H-indol-2-yl)pyrazin-2-ylamino)ethylcarbamate (54 mg, 0.18 mmol) in DMSO (1 mL) was added K₂CO₃ (59 mg, 0.43 mmol) and hydrogen peroxide (33% in water, 50 mg, 0.43 mmol). The mixture was stirred at 28° C. for 12 hours. Saturated Na₂S₂O₃ (50 mL) was added and the mixture was extracted with ethyl acetate (3×50 mL). The combined organics were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by prep-TLC (1:1 petroleum ether/EtOAc) to afford tert-butyl (2-{[5-carbamoyl-6-(1H-indol-2-yl)pyrazin-2-yl]amino}ethyl)carbamate as a solid. MS ESI calc'd. for C₂₀H₂₅N₆O₃ [M+H]⁺ 397, found 397. ¹H NMR (400 MHz, CD₃OD) δ 7.73 (s, 1H), 7.59-7.52 (m, 2H), 7.38 (s, 1H), 7.16 (t, J=7.2 Hz, 1H), 7.02 (t, J=7.2 Hz, 1H), 3.63 (t, J=6.0 Hz, 2H), 3.37 (t, J=6.0 Hz, 2H), 1.47 (s, 9H).

Step 3: To a mixture of tert-butyl (2-((5-carbamoyl-6-(1H-indol-2-yl)pyrazin-2-yl)amino)ethyl)carbamate (54 mg, 0.18 mmol) in DCM (3 mL) at 28° C. was added triethylsilane (367 mg, 3.15 mmol) and TFA (216 mg, 1.89 mmol) and the mixture was stirred for 3 hours. Aqueous saturated NaHCO₃ (50 mL) was added and the mixture was extracted with ethyl acetate (3×50 mL). The combined organics were dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by reverse phase HPLC to afford 5-(2-aminoethylamino)-3-(1H-indol-2-yl)pyrazine-2-carboxamide as the TFA salt. MS ESI calc'd. for C₁₅H₁₇N₆O [M+H]⁺ 297, found 297. ¹H NMR (400 MHz, CD₃OD) δ 7.82 (s, 1H), 7.58 (d, J=8.0 Hz, 1H), 7.45 (d, J=8.0 Hz, 1H), 7.35 (s, 1H), 7.18 (t, J=8.0 Hz, 1H), 7.05 (t, J=8.0 Hz, 1H), 3.86 (t, J=6.0 Hz, 2H), 3.29 (t, J=6.0 Hz, 2H).

Example 15 Example 15.1 5-{[2-Amino-3-(methylsulfonyl)propyl]amino}-3-(1H-indol-2-yl)pyrazine-2-carboxamide

Step 1: To a mixture of 3,5-dichloropyrazine-2-carbonitrile (68 mg, 0.39 mmol) in 2-methylpropan-2-ol (2 mL) was added tert-butyl 1-amino-3-(methylthio)propan-2-ylcarbamate (50 mg, 0.23 mmol), Hunig's base (101 mg, 0.780 mmol) under N₂. The mixture was heated to 50° C. under a N₂ atmosphere for 5 hours. Upon cooling to 25° C., the mixture was diluted with brine (50 mL) and extracted with ethyl acetate (3×50 mL). The combined organics were dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by prep-TLC (1:1 petroleum ether/EtOAc) to afford tert-butyl 1-(6-chloro-5-cyanopyrazin-2-ylamino)-3-(methylthio)propan-2-ylcarbamate as a solid. MS ESI calc'd. for C₁₄H₂₁ClN₅O₂S [M+H]⁺ 358, found 358. ¹H NMR (400 MHz, DMSO-d₆) δ 7.80 (s, 1H), 6.84 (s, 1H), 5.06 (s, 1H), 3.99-3.93 (m, 1H), 3.64-3.51 (m, 2H), 2.68-2.67 (m, 2H), 2.13 (s, 3H), 1.38 (s, 9H).

Step 2: To a mixture of tert-butyl 1-(6-chloro-5-cyanopyrazin-2-ylamino)-3-(methylthio)propan-2-ylcarbamate (200 mg, 0.560 mmol), (1-(tert-butoxycarbonyl)-1H-indol-2-yl)boronic acid (160 mg, 0.610 mmol), Pd₂(dba)₃ (26 mg, 30 μmol), Xphos (27 mg, 60 μmol) and K₃PO₄ (446 mg, 1.68 mmol) was added dioxane (2 mL) and H₂O (0.5 mL). The mixture was heated to 90° C. for 3 hours. Upon cooling to room temperature, H₂O (50 mL) was added and the mixture was extracted with ethyl acetate (3×50 mL). The combined organics were dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by prep-TLC (1:1 petroleum ether/EtOAc) to afford tert-butyl [1-{[5-cyano-6-(1H-indol-2-yl)pyrazin-2-yl]amino}-3-(methylsulfanyl)propan-2-yl]carbamate as a solid. MS ESI calc'd. for C₂₂H₂₇N₆O₂S [M+H]⁺ 439, found 439. ¹H NMR (400 MHz, CDCl₃) δ 8.19-8.17 (m, 1H), 7.89 (s, 1H), 7.81 (s, 1H), 7.63-7.61 (m, 1H), 7.42-7.38 (m, 1H), 7.30-7.28 (m, 1H), 7.00 (s, 1H), 6.69 (s, 1H), 6.21 (s, 1H), 4.02-3.99 (m, 2H), 3.70-3.68 (m, 2H), 3.57-3.55 (m, 1H), 2.17 (s, 3H), 1.60 (s, 9H).

Step 3: To a mixture of tert-butyl [1-{[5-cyano-6-(1H-indol-2-yl)pyrazin-2-yl]amino}-3-(methylsulfanyl)propan-2-yl]carbamate (20 mg, 50 mol) in DMSO (1 mL) at 28° C. was added K₂CO₃ (19 mg, 0.14 mmol) and hydrogen peroxide (33% in water, 16 mg, 0.14 mmol) and the mixture was stirred for 12 hours. Aqueous saturated Na₂S₂O₃ (50 mL) was added and the mixture was extracted with ethyl acetate (3×50 mL). The combined organics were dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to afford tert-butyl [1-{[5-carbamoyl-6-(1H-indol-2-yl)pyrazin-2-yl]amino}-3-(methylsulfinyl)propan-2-yl]carbamate as a yellow solid that was used in the subsequent reaction without further purification. MS ESI calc'd. for C₂₂H₂₉N₆O₄S [M+H]⁺ 473, found 473.

Step 4: To a mixture of tert-butyl [1-{[5-carbamoyl-6-(1H-indol-2-yl)pyrazin-2-yl]amino}-3-(methylsulfinyl)propan-2-yl]carbamate (70 mg, 0.15 mmol) in THF (0.5 mL) and H₂O (0.5 mL) at 0° C. was added Oxone (91 mg, 0.15 mmol) and the mixture was maintained at 0° C. for 2 hours. Saturated Na₂S₂O₃ (50 mL) was added and the mixture was extracted with ethyl acetate (3×50 mL). The combined organics were dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to afford tert-butyl 1-(5-carbamoyl-6-(1H-indol-2-yl)pyrazin-2-ylamino)-3-(methylsulfonyl)propan-2-ylcarbamate as a solid that was used in the subsequent reaction without further purification. MS ESI calc'd. for C₂₂H₂₉N₆O₅S [M+H]⁺ 489, found 489.

Step 5: To a mixture of tert-butyl 1-(5-carbamoyl-6-(1H-indol-2-yl)pyrazin-2-ylamino)-3-(methylsulfonyl)propan-2-ylcarbamate (80 mg, 0.16 mmol) in DCM (2 mL) at 28° C. was added triethylsilane (57 mg, 0.49 mmol) and TFA (56 mg, 0.49 mmol) and the mixture was stirred for 3 hours. Aqueous saturated NaHCO₃ (50 mL) was added and the mixture was extracted with ethyl acetate (3×50 mL). The combined organics were dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by reverse phase HPLC to afford 5-{[2-amino-3-(methylsulfonyl)propyl]amino}-3-(1H-indol-2-yl)pyrazine-2-carboxamide as the TFA salt. MS ESI calc'd. for C₁₇H₂₁N₆O₃S [M+H]⁺ 389, found 389. ¹H NMR (400 MHz, CD₃OD) δ 7.86 (s, 1H), 7.56 (d, J=8.0 Hz, 1H), 7.45 (d, J=8.0 Hz, 1H), 7.36 (s, 1H), 7.16 (t, J=8.0 Hz, 1H), 7.02 (t, J=8.0 Hz, 1H), 4.39-4.31 (m, 1H), 4.18-4.13 (m, 1H), 3.78-3.73 (m, 2H), 3.58-3.53 (m, 1H), 3.17 (s, 3H).

Example 16 Example 16.1 (R)-5-((1-amino-3-methoxypropan-2-yl)amino)-3-(1H-indol-2-yl)pyrazine-2-carboxamide

Step 1: To a mixture of (R)-tert-butyl (1-amino-3-methoxypropan-2-yl)carbamate oxalate salt (1.00 g, 3.40 mmol), Na₂CO₃ (1.08 g, 10.2 mmol) in THF (10 mL) and H₂O (2.5 mL) at 0° C. under a N₂ atmosphere was added benzyl carbonochloridate (754 mg, 4.42 mmol) dropwise. The mixture was allowed to warm to 25° C. for 6 hours. The mixture was diluted with brine (50 mL) and extracted with ethyl acetate (3×50 mL). The combined organics were dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by column chromatography on silica (5:1 petroleum ether/EtOAc) to afford (R)-benzyl tert-butyl (3-methoxypropane-1,2-diyl)dicarbamate as an oil. MS ESI calc'd. for C₁₇H₂₇N₂O₅ [M+H]⁺ 339, found 339. ¹H NMR (400 MHz, CDCl₃) δ 7.35-7.29 (m, 5H), 5.23 (s, 1H), 5.08 (s, 2H), 5.02 (s, 1H), 3.79 (s, 1H), 3.46-3.38 (m, 4H), 3.31 (s, 3H), 1.40 (s, 9H).

Step 2: A mixture of (R)-benzyl tert-butyl (3-methoxypropane-1,2-diyl)dicarbamate (700 mg, 2.07 mmol) in HCl (4.0 N in MeOH, 10.0 mL, 40 mmol) was stirred at 28° C. for 6 hours. Aqueous saturated NaHCO₃ (50 mL) was added and the mixture was extracted with ethyl acetate (3×50 mL). The combined organics were dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by column chromatography on silica (1:1 petroleum ether/EtOAc) to afford (R)-benzyl (2-amino-3-methoxypropyl)carbamate as a solid. MS ESI calc'd. for C₁₂H₁₉N₂O₃[M+H]⁺ 239, found 239. ¹H NMR (400 MHz, DMSO-d₆) δ 8.41 (s, 2H), 8.05 (s, 1H), 7.46-7.30 (m, 5H), 5.02 (s, 2H), 3.60-3.50 (m, 2H), 3.30 (s, 3H), 3.23-3.22 (m, 2H), 3.05-3.04 (m, 1H).

Step 3: A mixture of (R)-benzyl (2-amino-3-methoxypropyl)carbamate (500 mg, 2.10 mmol), 3,5-dichloropyrazine-2-carbonitrile (632 mg, 3.63 mmol) and Hunig's base (936 mg, 7.24 mmol) in 2-methylpropan-2-ol (2.3 mL) was heated to 50° C. for 6 hours. Upon cooling to 28° C., saturated aqueous NH₄Cl (50 mL) was added and the mixture was extracted with ethyl acetate (3×50 mL). The combined organics were dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by column chromatography on silica (1:1 petroleum ether/EtOAc) to afford (R)-benzyl (2-((6-chloro-5-cyanopyrazin-2-yl)amino)-3-methoxypropyl)carbamate as a solid. MS ESI calc'd. for C₁₇H₁₉ClN₅O₃ [M+H]⁺ 376, found 376. ¹H NMR (400 MHz, CDCl₃) δ 7.77 (s, 1H), 7.36-7.33 (m, 5H), 6.35 (s, 1H), 5.14-5.09 (m, 2H), 4.31 (s, 1H), 3.61-3.50 (m, 5H), 3.39 (s, 3H).

Step 4: A mixture of (R)-benzyl (2-((6-chloro-5-cyanopyrazin-2-yl)amino)-3-methoxypropyl) carbamate (200 mg, 0.532 mmol), (1-(tert-butoxycarbonyl)-1H-indol-2-yl)boronic acid (181 mg, 0.692 mmol), Pd₂(dba)₃ (24 mg, 0.027 mmol), Xphos (25 mg, 0.053 mmol) and K₃PO₄ (425 mg, 1.60 mmol) in dioxane (2 mL) and H₂O (0.5 mL) was heated to 90° C. for 3 hours. Upon cooling to room temperature, H₂O (50 mL) was added and the mixture was extracted with ethyl acetate (3×50 mL). The combined organics were dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by column chromatography on silica (1:1 petroleum ether/EtOAc) to afford crude (R)-tert-butyl-2-(6-(1-(benzyloxycarbonylamino)-3-methoxypropan-2-ylamino)-3-cyanopyrazin-2-yl)-1H-indole-1-carboxylate as a solid that was used in the subsequent reaction without further purification. MS ESI calc'd. for C₃₀H₃₃N₆O₅ [M+H]⁺ 557, found 557.

Step 5: To a mixture of (R)-tert-butyl 2-(6-((1-(((benzyloxy)carbonyl)amino)-3-methoxypropan-2-yl) amino)-3-cyanopyrazin-2-yl)-1H-indole-1-carboxylate (80 mg, 0.14 mmol) in DCM (5 mL) was added TFA (0.5 mL) and the mixture was stirred at 28° C. for 6 hours. Aqueous saturated NaHCO₃ (50 mL) was added and the mixture was extracted with ethyl acetate (3×50 mL). The combined organics were dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to afford (R)-benzyl (2-((5-cyano-6-(1H-indol-2-yl)pyrazin-2-yl)amino)-3-methoxypropyl)carbamate as a solid that was used in the subsequent reaction without further purification. MS ESI calc'd. for C₂₅H₂₅N₆O₃ [M+H]⁺ 457, found 457.

Step 6: To a mixture of (R)-benzyl (2-((5-cyano-6-(1H-indol-2-yl)pyrazin-2-yl)amino)-3-methoxypropyl)carbamate (30 mg, 0.068 mmol) in DMSO (1 mL) was added K₂CO₃ (28 mg, 0.21 mmol) and hydrogen peroxide (33% aqueous, 23 mg, 0.21 mmol) and the mixture was stirred at 28° C. for 12 hours. Aqueous saturated Na₂S₂O₃ (50 mL) was added and the mixture was extracted with ethyl acetate (3×50 mL). The combined organics were dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by prep-TLC (1:1 petroleum ether/EtOAc) to afford (R)-benzyl-2-(5-carbamoyl-6-(1H-indol-2-yl)pyrazin-2-ylamino)-3-methoxypropylcarbamate as a solid. MS ESI calc'd. for C₂₅H₂₇N₆O₄ [M+H]⁺ 475, found 475. ¹H NMR (400 MHz, CDCl₃) δ 12.95 (s, 1H), 7.86 (s, 1H), 7.76 (s, 1H), 7.68-7.66 (m, 1H), 7.51-7.49 (m, 1H), 7.30-7.29 (m, 3H), 7.23-7.22 (m, 3H), 7.11-7.09 (m, 1H), 5.14-5.06 (m, 2H), 3.71-3.59 (m, 5H), 3.43 (s, 3H).

Step 7: To a mixture of (R)-benzyl-2-(5-carbamoyl-6-(1H-indol-2-yl)pyrazin-2-ylamino)-3-methoxypropylcarbamate (25 mg, 0.053 mmol) in methanol (5 mL) at 25° C. was added di-tert-butyl dicarbonate (17 mg, 0.079 mmol), TEA (16 mg, 0.16 mmol) and Pd/C (2.5 mg). The mixture was evacuated and purged with hydrogen five times and then stirred for 12 hours under a hydrogen atmosphere. The mixture was filtered and concentrated under reduced pressure to afford (R)-tert-butyl(2-((5-carbamoyl-6-(1H-indol-2-yl)pyrazin-2-yl)amino)-3-methoxypropyl)carbamate as a solid that was used in the subsequent reaction without further purification. MS ESI calc'd. for C₂₂H₂₉N₆O₄ [M+H]⁺ 441, found 441.

Step 8: To a mixture of (R)-tert-butyl (2-((5-carbamoyl-6-(1H-indol-2-yl)pyrazin-2-yl)amino)-3-methoxypropyl)carbamate (30 mg, 0.068 mmol) in DCM (5 mL) at 28° C. was added triethylsilane (24 mg, 0.20 mmol) and TFA (21 mg, 0.18 mmol) and the mixture was stirred for 6 hours. Aqueous saturated NaHCO₃ (50 mL) was added and the mixture was extracted with ethyl acetate (3×50 mL). The combined organics were dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by reverse phase HPLC to afford (R)-5-((1-amino-3-methoxypropan-2-yl)amino)-3-(1H-indol-2-yl)pyrazine-2-carboxamide as the TFA salt. MS ESI calc'd. for C₁₇H₂₁N₆O₂ [M+H]⁺ 341, found 341. ¹H NMR (400 MHz, CD₃OD) δ 7.88-7.85 (m, 1H), 7.59-7.57 (m, 1H), 7.46-7.44 (m, 1H), 7.37-7.36 (m, 1H), 7.20-7.16 (m, 1H), 7.05-7.03 (m, 1H), 3.88-3.74 (m, 2H), 3.66-3.55 (m, 2H), 3.46 (s, 3H), 3.26-3.25 (m, 1H).

The following compound was prepared in an analogous manner of that described in Example 16.1.

Ex. [M + H]+ [M + H]+ No. Structure Name Calc'd Obsv'd Form 16.2

(S)-5-((1-amino-3- methoxypropan-2- yl)amino)-3-(1H-indol-2- yl)pyrazine-2-carboxamide 341 341 TFA Salt Biological Assay Homogeneous Time-Resolved Fluorescence (HTRF) Assay For The Recombinant Human Syk Enzyme

A recombinant GST-hSYK fusion protein was used to measure potency of compounds to inhibit human Syk activity. The recombinant human GST-SYK (Carna Biosciences #08-176) (5 pM final concentration) was incubated with various concentrations of the inhibitor diluted in DMSO (0.1% final concentration) for 10 minutes at room temperature in 15 mM Tris-HCl (pH 7.5), 0.01% tween 20, 2 mM DTT in 384 well plate format. To initiate the reaction the biotinylated substrate peptide (250 nM final concentration) that contains the phosphorylation site for Syk was added with magnesium (5 mM final concentration) and ATP (25 μM final concentration). Final volume of the reaction was 10 μL. Phosphorylation of the peptide was allowed to proceed for 45′ at room temperature. To quench the reaction and detect the phosphorylated product, 2 nM of a Europium-anti-phosphotyrosine antibody (Perkin Elmer #AD0161) and 70 nM SA-APC (Perkin-Elmer #CR130-100) were added together in 15 mM Tris pH 7.5, 40 mM EDTA, 0.01% tween 20. Final volume of the quenching solution was 10 μL.

The resulting HTRF signal was measured after 30 minutes on an EnVision (Perkin-Elmer) reader using a time-resolved fluorescence protocol. Table A below lists activities as IC₅₀ values (nM) for representative compounds of the invention.

TABLE A Ex. No. IC₅₀ 1.1 528.0 2.1 0.5 2.2 5.2 3.1 2.5 4.1 0.8 5.1 0.6 6.1 3.7 7.1 0.2 7.2 0.4 7.3 0.5 7.4 5.9 7.5 0.6 7.6 1.2 7.7 1.3 7.8 0.9 7.9 3.1 7.10 1.2 8.1 6.4 8.2 124.1 8.3 1.3 8.4 2.1 8.5 0.7 8.6 1.3 8.7 1.0 9.1 13.4 10.1 3.0 10.2 0.8 10.3 0.5 10.4 0.5 10.5 0.2 10.6 4.1 10.7 4.1 10.8 1.6 10.9 5.2 11.1 991.5 12.1 2.2 12.2 2469.0 13.1 0.3 14.1 13.9 15.1 29.1 16.1 21.6 16.2 27.2

While the present invention has been described in conjunction with the specific embodiments set forth above, many alternatives, modifications and other variations thereof will be apparent to those of ordinary skill in the art. All such alternatives, modifications and variations are intended to fall within the spirit and scope of the present invention. 

What is claimed is:
 1. A compound of the Formula (I)

or a pharmaceutically acceptable salt thereof, wherein X is N(H) or O; B is a 5- to 10-membered mono- or bicyclic heteroaryl optionally containing 1 heteroatom in addition to the illustrated X atom, selected from the group consisting of N, O, and S; wherein B is unsubstituted or substituted by one to three R³ moieties, wherein each R³ moiety is independently selected from the group consisting of C₁-C₃ alkyl, C₁-C₃ alkoxy, C₁-C₃ fluoroalkyl, C₁-C₃ hydroxyalkyl, di(C₁-C₃ alkyl)sulfonium, halo, hydroxy, amino, (C₁-C₃ alkyl)amino, di(C₁-C₃ alkyl)amino, —N(H)SO₂—(C₁-C₃ alkyl), —CO₂H, —C(O)NH₂, —C(O)N(H)(C₁-C₃ alkyl), —C(O)N(H)(C₁-C₃ alkyl)₂, —CH₂O—(C₁-C₄ alkylene)-OH, phenyl, methyl pyrazolyl, pyridyl, and —CH₂CH₂-pyrrolidon-2-yl; or two R³ moieties when substituted on adjacent carbon atoms of B, together with their attached carbon atoms, form a dioxanyl or dioxolanyl ring; A is selected from the group consisting of:

wherein Y is —CH₂—, —S(O)₂—, or —O—; R¹¹ and R¹² are independently H or F; and the subscript n is 1 or 2; the subscript n′ is 0 or 1; or

wherein R^(a) and R^(b) are independently H, C₁-C₃ alkyl, or (C₁-C₃ alkoxy)methyl; R^(c) is H, C₁-C₆ alkyl, C₁-C₃ fluoroalkyl, C₃-C₆ cycloalkyl, —(CH₂)_(r)OR¹³, —C(O)NH₂, —C(O)N(H)(C₁-C₃ alkyl), —C(O)N(C₁-C₃ alkyl)₂, —(CH₂)_(r)S(O)_(t)R¹⁴, —(CH₂)_(r)-phenyl, or —(CH₂)_(r)N(H)C(O)—(C₁-C₃ alkyl); R¹³ is H or C₁-C₃ alkyl; and R¹⁴ is C₁-C₃ alkyl; the subscript r is 1 or 2; the subscript t is 0, 1, or 2; R^(d) is H or C₁-C₃ alkyl.
 2. The compound of claim 1 or a pharmaceutically acceptable salt thereof, wherein B is selected from the group consisting of:

wherein B is unsubstituted or substituted by one to two R³ moieties.
 3. The compound of claim 2 or a pharmaceutically acceptable salt thereof, wherein B is unsubstituted or substituted by one to two R³ moieties selected from the group consisting of chloro, fluoro, bromo, methyl, ethyl, trifluoromethyl, methoxy, phenyl, dimethylsulfonium, pyridyl, and —CH₂CH₂-pyrrolidon-2-yl.
 4. The compound of claim 1 or a pharmaceutically acceptable salt thereof, wherein: A is

Y is —CH₂—, —S(O)₂—, or —O—; R¹¹ and R¹² are independently H or F; and the subscript n is 1 or 2; and the subscript n′ is 0 or
 1. 5. The compound of claim 4 or a pharmaceutically acceptable salt thereof, wherein A is selected from the group consisting of:


6. The compound of claim 5 or a pharmaceutically acceptable salt thereof, wherein A is selected from the group consisting of:


7. The compound of claim 1 or a pharmaceutically acceptable salt thereof, wherein A is

wherein R^(a) and R^(b) are independently H, C₁-C₃ alkyl, or (C₁-C₃ alkoxy)methyl; R^(c) is H, C₁-C₆ alkyl, C₁-C₃ fluoroalkyl, C₃-C₆ cycloalkyl, —(CH₂)_(r)OR¹³, —C(O)NH₂, —C(O)N(H)(C₁-C₃ alkyl), —C(O)N(C₁-C₃ alkyl)₂, —(CH₂)_(r)S(O)_(t)R¹⁴, —(CH₂)_(r)-phenyl, or —(CH₂)_(r)N(H)C(O)—(C₁-C₃ alkyl); R¹³ is H or C₁-C₃ alkyl; and R¹⁴ is C₁-C₃ alkyl; the subscript r is 1 or 2; the subscript t is 0, 1, or 2; and R^(d) is H or C₁-C₃ alkyl.
 8. The compound of claim 7 or a pharmaceutically acceptable salt thereof, wherein R^(a) is H or methoxymethyl; R^(b) is H; R^(c) is H, methyl, methoxymethyl, or —CH₂SO₂CH₃; and R^(d) is H.
 9. The compound of claim 1 selected from the group consisting of: (S)-5-((2-aminopropyl)amino)-3-(benzofuran-2-yl)pyrazine-2-carboxamide; 5-(((1R,2S)-2-aminocyclohexyl)amino)-3-(1H-indol-2-yl)pyrazine-2-carboxamide; 5-{[(2S)-2-aminopropyl]amino}-3-(1H-indol-2-yl)pyrazine-2-carboxamide; 5-(((3S,4S)-4-amino-1,1-dioxidotetrahydro-2H-thiopyran-3-yl)amino)-3-(1H-indol-2-yl)pyrazine-2-carboxamide; (S)-5-((2-aminopropyl)amino)-3-(5-bromo-1H-indol-2-yl)pyrazine-2-carboxamide; (S)-5-((2-aminopropyl)amino)-3-(5-(1-methyl-1H-pyrazol-4-yl)-1H-indol-2-yl)pyrazine-2-carboxamide; (S)-5-((2-aminopropyl)amino)-3-(5-(2-(2-oxopyrrolidin-1-yl)ethyl)-1H-indol-2-yl)pyrazine-2-carboxamide; 5-{[(1R,2S)-2-aminocyclohexyl]amino}-3-(5-chloro-1H-indol-2-yl)pyrazine-2-carboxamide; 5-{[(2S)-2-aminopropyl]amino}-3-(4-bromo-1H-indol-2-yl)pyrazine-2-carboxamide; 5-[(3-aminotetrahydro-2H-pyran-4-yl)amino]-3-(4-chloro-1H-indol-2-yl)pyrazine-2-carboxamide; 5-[(3-aminotetrahydro-2H-pyran-4-yl)amino]-3-(4-chloro-1H-indol-2-yl)pyrazine-2-carboxamide; 5-{[(3R,4R)-3-aminotetrahydro-2H-pyran-4-yl]amino}-3-(5-methoxy-1H-indol-2-yl)pyrazine-2-carboxamide; 5-{[(3R,4R)-3-aminotetrahydro-2H-pyran-4-yl]amino}-3-(6-fluoro-1H-indol-2-yl)pyrazine-2-carboxamide; 5-{[(3S,4S)-4-amino-1,1-dioxidotetrahydro-2H-thiopyran-3-yl]amino}-3-(4-chloro-1H-indol-2-yl)pyrazine-2-carboxamide; 5-{[(3S,4S)-4-amino-1,1-dioxidotetrahydro-2H-thiopyran-3-yl]amino}-3-(5-methoxy-1H-indol-2-yl)pyrazine-2-carboxamide; 5-{[(3S,4S)-4-amino-1,1-dioxidotetrahydro-2H-thiopyran-3-yl]amino}-3-(5-fluoro-1H-indol-2-yl)pyrazine-2-carboxamide; 5-{[(3S,4S)-4-amino-1,1-dioxidotetrahydro-2H-thiopyran-3-yl]amino}-3-(5-chloro-1H-indol-2-yl)pyrazine-2-carboxamide; (R)-5-((2-amino-3-methoxypropyl)amino)-3-(1H-indol-2-yl)pyrazine-2-carboxamide; 5-{[(3R,4R)-4-amino-1,1-dioxidotetrahydro-2H-thiopyran-3-yl]amino}-3-(1H-indol-2-yl)pyrazine-2-carboxamide; 5-{[(1R,2S)-2-aminocyclohexyl]amino}-3-(4-methyl-1H-indol-2-yl)pyrazine-2-carboxamide; 5-{[(3R,4R)-3-aminotetrahydro-2H-pyran-4-yl]amino}-3-(4-methyl-1H-indol-2-yl)pyrazine-2-carboxamide; 5-{[(3R,4R)-3-aminotetrahydro-2H-pyran-4-yl]amino}-3-(4-methoxy-1H-indol-2-yl)pyrazine-2-carboxamide; 5-{[(3R,4R)-3-aminotetrahydro-2H-pyran-4-yl]amino}-3-(1H-indol-2-yl)pyrazine-2-carboxamide; 5-{[(2R)-2-amino-3-methoxypropyl]amino}-3-(4-methoxy-1H-indol-2-yl)pyrazine-2-carboxamide; 5-[(2-aminoethyl)amino]-3-(5-fluoro-1H-indol-2-yl)pyrazine-2-carboxamide; 5-(((3R,4R)-3-aminotetrahydro-2H-pyran-4-yl)amino)-3-(4-methoxy-1H-pyrrolo[2,3-c]pyridin-2-yl)pyrazine-2-carboxamide; 5-(((3S,4S)-4-amino-1,1-dioxidotetrahydro-2H-thiopyran-3-yl)amino)-3-(5-(trifluoromethyl)-1H-indol-2-yl)pyrazine-2-carboxamide; 5-{[(3R,4R)-3-aminotetrahydro-2H-pyran-4-yl]amino}-3-(2,3-dihydro-7H-[1,4]dioxino[2,3-e]indol-8-yl)pyrazine-2-carboxamide; 5-{[(3R,4R)-3-aminotetrahydro-2H-pyran-4-yl]amino}-3-(4,5-dimethoxy-1H-indol-2-yl)pyrazine-2-carboxamide; 5-{[(3R,4R)-3-aminotetrahydro-2H-pyran-4-yl]amino}-3-(5-ethyl-1H-indol-2-yl)pyrazine-2-carboxamide; 5-{[(3R,4R)-3-aminotetrahydro-2H-pyran-4-yl]amino}-3-(4-ethyl-1H-indol-2-yl)pyrazine-2-carboxamide; 5-{[(3R,4R)-3-aminotetrahydro-2H-pyran-4-yl]amino}-3-(1H-pyrrolo[3,2-c]pyridin-2-yl)pyrazine-2-carboxamide; 5-{[(3R,4R)-3-aminotetrahydro-2H-pyran-4-yl]amino}-3-(1H-pyrrolo[3,2-b]pyridin-2-yl)pyrazine-2-carboxamide; 5-{[(3R,4R)-3-aminotetrahydro-2H-pyran-4-yl]amino}-3-(1H-pyrrolo[2,3-c]pyridin-2-yl)pyrazine-2-carboxamide; 5-(((3S,4S)-4-amino-1,1-dioxidotetrahydro-2H-thiopyran-3-yl)amino)-3-(3-chloro-1H-indol-2-yl)pyrazine-2-carboxamide; (2-(6-(((3S,4S)-4-amino-1,1-dioxidotetrahydro-2H-thiopyran-3-yl)amino)-3-carbamoylpyrazin-2-yl)-1H-indol-3-yl)dimethylsulfonium; (S)-5-((2-aminopropyl)amino)-3-(5-(pyridin-3-yl)-1H-indol-2-yl)pyrazine-2-carboxamide; 5-(2-aminoethylamino)-3-(1H-indol-2-yl)pyrazine-2-carboxamide; 5-{[2-amino-3-(methylsulfonyl)propyl]amino}-3-(1H-indol-2-yl)pyrazine-2-carboxamide; (R)-5-((1-amino-3-methoxypropan-2-yl)amino)-3-(1H-indol-2-yl)pyrazine-2-carboxamide; and (S)-5-((1-amino-3-methoxypropan-2-yl)amino)-3-(1H-indol-2-yl)pyrazine-2-carboxamide; or a pharmaceutically acceptable salt thereof.
 10. The compound of claim 9 selected from the group consisting of: 5-(((3S,4S)-4-amino-1,1-dioxidotetrahydro-2H-thiopyran-3-yl)amino)-3-(1H-indol-2-yl)pyrazine-2-carboxamide; 5-{[(3R,4R)-3-aminotetrahydro-2H-pyran-4-yl]amino}-3-(5-methoxy-1H-indol-2-yl)pyrazine-2-carboxamide; 5-{[(1R,25)-2-aminocyclohexyl]amino}-3-(4-methyl-1H-indol-2-yl)pyrazine-2-carboxamide; 5-{[(3R,4R)-3-aminotetrahydro-2H-pyran-4-yl]amino}-3-(4-methoxy-1H-indol-2-yl)pyrazine-2-carboxamide; and (S)-5-((2-aminopropyl)amino)-3-(5-(pyridin-3-yl)-1H-indol-2-yl)pyrazine-2-carboxamide; or a pharmaceutically acceptable salt thereof.
 11. A pharmaceutical composition comprising a therapeutically effective amount of the compound of claim 1 or a pharmaceutically acceptable salt thereof and a pharmaceutically acceptable carrier.
 12. The compound of claim 1, which is 5-(((3S,4S)-4-amino-1,1-dioxidotetrahydro-2H-thiopyran-3-yl)amino)-3-(1H-indol-2-yl)pyrazine-2-carboxamide, or a pharmaceutically acceptable salt thereof. 